Some questions about the LGBT's flags, and their colors

To start with, I’m just a young guy with a lot of questions swirling around in my head. And to be honest, I don’t know much about this community, which I’m sorry about.

While doing a simple Google search for “LGBT flags,” I came across several flags I hadn’t known about before. For example, the asexual flag, the gay men’s flag, and so on.

So a question came to mind: how are the colors of these flags chosen?

And a second one (which I hope won’t lead to heated debates): doesn’t having so many sub-groups sometimes lead to conflicts?

Thanks in advance for your answers! And I hope I don’t come across as too sheltered when it comes to this community