Some questions on Non-binary/ Transgender

Hello! I hope you are having a nice day so far.

I have some questions regarding people who identify as non-binary/transgender. Even if you do not identify as a non-binary or transgender person, your answers are most definitely appreciated.

For some context, I recently discovered the term non-binary/ gender fluid on my instagram stories (I already knew about transgender people.) I am very sceptical about most of the content they post, because some of them contain false information. For a couple of months, I tried doing some research, but I cannot understand at all. I have searched on certified medical websites, but there was no official study to be found. I went on Youtube and saw some videos on non-binary people. However that did not help in the slightest.

Here are some questions I have:

1. What are the main elements that define being non-binary? (an example would be how gay people are attracted to men or transgender people identify to the opposite gender than they were born with.)

2. From what I have seen, non-binary is often associated with transgender. One of my closest friends is a transgender person (female to male) and he has gender dysphoria. Recently I have heard statements that you do not need to have gender dysphoria to be trans. Is that true? Do non-binary people need to be diagnosed with gender dysphoria as well?

3. The non-binary people that I have seen on Youtube often talk about how wearing different types of clothing or having different hobbies has made them identify as non-binary. An example would be if that person use to identify as female, but all the sudden, wearing suits and more manly clothing made her question whether she can completely identify as female. I don't understand this, because whatever you wear does not really stray from your gender. Is this true?

These questions may sound a bit ignorant from my part, because I am young and a lot of people my age already know about this. I am scared to ask on larger social media platforms such as Twitter or Instagram, because many people are very aggressive about their responses on these types of subjects. I have been on Mangago for some time and I thought this would be a good place to start since that many users are very open and kind.

I made my account today to post with question. I haven't before, because I was skeptical about making an account here. I also look forward to meet many users and to be more active on discussions.