Florian's Post

@bun GitHub, from a user's perspective, is generally just a place where developers can put their projects for themselves and others to work on. The README of a project on GitHub will generally have instructions on how to actually download/obtain the software in question and if not, you can see if any releases were published for the projects you're interested in. Those would be where actual downloads can be found.
Contributing to projects on there is a bit trickier and kinda depends on what you'd want to do :)