I know this document seems long, but it shouldn't be too difficult to follow. This guide is based on Windows, but every program here has Linux/Mac equivalents, and in most cases they're built-in. So, take a deep breath and go step by step.
The steps below are for GitHub, but the steps are almost idential for Bitbucket, Heroku, etc.
You'll probably want to make sure Chocolatey is installed, since it streamlines installing this stuff later. If you install via Chocolatey, you don't need to run the installers from the products' respective sites.