That's really not a silly question at all, LDC. The answer isn't totally straightforward though.
First of all, yes, some of the big professional organisations do have links on their websites. For example you can go here:
https://www.aap.org/en-us/advocacy-...AP-Health-Initiatives.aspx#SchoolandChildCare
...to find out the American Academy of Pediatrics' recommendations and support programmes on everything from breastfeeding, alcohol use in pregnancy and vaccination to childproofing and media consumption.
Something like that is kind of a one-stop-shop for advice from a reputable institution that regularly reviews scientific literature. A lot of these recommendations will be passed down through professional channels, like doctors and nurses.
Sometimes though, you need a bit more help/want to know more about something specific and a one-stop shop doesn't give you enough, so you can go to some of the specialist organisations, like La Leche League, CDC, etc, and they can give you a lot more of the 'why' behind the recommendations. They tend to have an 'approach' or a particular advocacy position. For topics like media consumption, there are organisations like CommonSenseMedia which are particularly devoted to the issue, or children's advocacy organisations like Children Now, which address it as part of their remit.
On most of these sites you can find links to studies and further information on pretty much whatever topic you're interested in. Stuff like sleep help tends to be more the domain of self-appointed 'professionals' who may or may not have a lot of scientific evidence behind what they 'teach'.
So, if you want to look studies up directly yourself, I find the best way is to search relatively neutral terms like, say "Sleep training infants" on Google Scholar. That way you'll find a range of studies that address the topic that won't necessarily be loaded either way (eg if you searched "Damage sleep training" you'd get a rather different set of results). Other people might have different advice for searching this way.
You might feel common sense will see you right, and that's an approach a lot of people take. My feeling is that common sense is not that common, by which I mean that you can take a lot of people from approximately the same demographic group and their 'common sense' opinions will vary hugely.
My OH, for example, is an intelligent and sensitive man who I was astounded to discover was under the impression that it was normal and fine to leave a 10-day infant to 'cry it out' in a separate room with the door closed. (This never actually happened, he just made the suggestion under stress at 3am one day.) 'Common sense' is a very nebulous term for a general feeling that's incredibly dependent on your own background, personality, media exposure, education level, interests, etc etc etc.
I mean, take this for example: https://www.prnewswire.com/news-rel...ramatically-from-five-years-ago-82132757.html
This says (and I've seen similar figures elsewhere that on average American kids 8-18 are using media devices for 53 hours a week. ON AVERAGE. That means a lot of kids are using them a lot more than that.
Now call me conservative, but there doesn't seem to be a lick of common sense in that. And yet - that's just reality. Normal. That's what a lot of parents think is totally fine.
That's why I personally don't trust common sense. I think raising a child is one of the most important and challenging things you can do and personally, I think it's worth it to spend more time doing some reading and research than going with an 'instinct' about what's right, which is inevitably going to be shaped by the opinions and preferences of those who are closest to me (relatives, friends) or loudest (media, teachers, advertisers).