>>29836212Codefag here. You need to install the tool named "git". It's a "version control system", a coder tool to manage source code and update it granularly and that stuff.
While, technically, you can just "download zip" at the github site (
https://github.com/citra-emu/citra) it won't pull some extra dependencies, so you are going to need git for it.
Google up on how to install git for your system, then you do "git clone --recursive
https://github.com/citra-emu/citra" and that will give you all the source code to build from.
Note that you still have to build it yourself in that case.
It's super easy to do in linux, I just did without having to install anything extra for it, but that's probably not your case. I can't help you in how to build for windows, unfortunately.