How does one come to a conclusion and be confident that they are correct?

Apart from personal experience, where the truth is reasonably certain, learning from outside sources means the truth is really uncertain unless supported by EVIDENCE. Even then one must be sure the evidence is TRUE, because it can be deliberately false, or be incorrect from human fallibility, ignorance, partiality or simply limited understanding.

Outside sourced information requires credible confirmation or at least have come from credible sources, else it is useless and unreliable as a basis for knowledge and understanding.  As the average person is relying on radio, TV, internet or newsprint media as sources, the possibilities become immense.

It seems that the vast majority of the public are satisfied with accrediting credibility to the mainstream media outlets, apparently without a great deal of questioning. Without questioning and accepted verification, there remains a potential risk of misinformation, limited information and even deliberate lies being believed. Why not accept the information at face value? Why not trust the sources?
Because there exist numerable factors challenging the credibility and impartiality of the MSM information. [A subject deserving separate clarification, but the aim here is to support alternative sources]
Because there are alternative viewpoints which deserve to be addressed.

How do we know there are opposing viewpoints? Because, for one, there exists a global, publicly accessible Internet system. An information source quickly and strongly criticised by the MSM as completely unreliable!
And it may be, in part, because the information sources vary greatly in their content reliability and author competence and impartiality.
The Internet contains, public social networking programs such as Face Book giving ‘voice’ to all and sundry, opinions, personal information, debates etc.,
But it also contains a wealth of technical and professional data and information from legitimate, professional experts, covering world-wide an endless range of subjects. To ignore this genuine source is being very short-sighted indeed, and is illogical.
Such information also requires scrutiny, or proof as to its credibility, which if not provided within, is available by using a reputable search engine.

A case in point!  
The only subject of real importance to the public, currently, is of course, “Covid”, the virus and the “vaccines”! There are surely matters of “life and death”, livelihoods and sanity, which deserve comprehensive, truthful coverage without confusion or censorship.
[ By the way, the MSM and its ardent followers, love to quote “follow the science”, not necessarily having a clue about science anyway, but accepting the TV version which claims that their information is based on “science”, but completely without any evidence, publishing of data or correct use of scientific methods.]

Legitimising internet sources:

Doctors of qualification, experience and courage.

America’s Frontline Doctors:    [ https://americasfrontlinedoctors.org/about-us/ ]
Today the facts remain the same: SARS-CoV-2 poses virtually no mortality risk to people up to 70 years old. For those beyond 70, survival approaches 95%, and with early treatment is nearly 100% survivable.
Today the problems with the “vaccines” remain the same: none have been studied for long-term effects, and the short-term toxicity is already alarming. The Vaccine Adverse Event Reporting System (VAERS), run by the CDC, shows over 15,000 deaths following COVID vaccines.
Today lies about vaccines remain the same: The CDC lied when it said: “If you get the shot, you are protected from COVID. If you get the booster, you are protected from COVID.” Finally, CDC Director Walensky had to admit this was false because the shots are completely worthless against Delta and (ironically due to the shots!) Delta is all there is now.
One of the biggest lies is that people with natural immunity need the shot. This lie is dangerous. If you are COVID-recovered and take the shot, you are not only not getting any benefit, but you are at HIGHER risk of a serious adverse event including death. Protecting the COVID-recovered is the basis for two of our lawsuits.
If you are being coerced to have the vaccine by your employer, do not quit your job in protest. And do not resign if your employer pressures you to resign. Keep showing up and doing your work.
By forcing your employer to fire you, you may be entitled to unemployment benefits, and your employer must pay the costs for this. Companies that choose to force vaccination upon their employees as a condition to maintain their job must be made to feel the financial pain associated with their choices.

Also people are waking up and pulling back from vaccine mandates (University of Alabama.)
America’s Frontline Doctors is in this fight 100%.

https://www.lifesitenews.com/blogs/4200-physicians-sign-declaration-for-early-treatment-of-covid-19-against-govt-intrusion/
“ (LifeSiteNews) — Earlier this month a physicians’ and medical scientists’ declaration was written by a team under the leadership of Dr. Robert Malone, the main inventor of the mRNA technology and a strong critic of the current official response to COVID-19. This text, which defends physicians’ right to treat corona patients with the best knowledge of early treatments and against  aggressive intrusion by governmental entities, has now gained 4,200 signatures from other physicians and medical scientists.”

Covid – Hundreds of Medical Practitioners Critical of ‘Official’ Procedures.
A sample:

“·  Dr. Nancy Banks – http://bit.ly/1Ip0aIm

• Dr. Russell Blaylock – http://bit.ly/1BXxQZL
• Dr. Shiv Chopra – censored
• Dr. Sherri Tenpenny – http://bit.ly/1MPVbjx
• Dr. Suzanne Humphries – http://bit.ly/17sKDbf
• Dr. Larry Palevsky – http://bit.ly/1LLEjf6
• Dr. Toni Bark – censored
• Dr. Andrew Wakefield – censored
• Dr. Meryl Nass – http://bit.ly/1DGzJsc
• Dr. Raymond Obomsawin – http://bit.ly/1G9ZXYl
• Dr. Ghislaine Lanctot – censored
• Dr. Robert Rowen – http://bit.ly/1SIELeF
• Dr. David Ayoub – http://bit.ly/1SIELve
• Dr. Boyd Haley PhD – http://bit.ly/1KsdVby
• Dr. Rashid Buttar – censored
• Dr. Roby Mitchell – censored
• Dr. Ken Stoller – http://bit.ly/1MPVqLI
• Dr. Mayer Eisenstein – censored
• Dr. Frank Engley, PhD – censored
• Dr. David Davis – http://bit.ly/1gdgJwo

and a great many more!

 Other news sources providing credible information:
https://healthimpactnews.com/2021/covid-shots-are-killing-and-crippling-teens-in-record-numbers-young-children-are-next/

“September 2, 2021
COVID Shots Are Killing and Crippling Teens in Record Numbers – Young Children Are Next

by Brian Shilhavy
Editor, Health Impact NewsCOVID-19 “vaccines” are killing and destroying the lives of many teens. This is the true “pandemic” facing our society now, as we are seeing a record number of injuries and deaths in people so young, and previously healthy, after taking one of the COVID-19 shots.

The FDA and CDC’s own statistics in their Vaccine Adverse Event Reporting System (VAERS) database actually implicate them in their crimes against humanity, and yet most people are still sleeping and deluded by the Big Pharma-funded corporate media which continues to lie to the American people on a daily basis.

All these and more, are of vital importance in establishing if the public is getting legitimate health care and treatments, health-wise and freedom-wise!

More so, it is quite clear that medical information from the internet can be, and certainly is reliable, if the information is scientifically credible!