It’s a pretty advanced thing to do. I don’t recommend it.
You can have a look at Set up Discourse on a server with existing Apache sites. That is the step by step guide that your seek, but I’m afraid the steps will be hard to make sense of if you’ve just started out with this stuff.
If you can successfully move your servers from regular hosting to your own server, then you can consider trying to add discourse to the mix.
Also, I wouldn’t try without at least 4gb of ram.