Sign in

When you launch GitHub Desktop for the first time, you'll be prompted to sign in. It'll probably take you to a web browser. When it returns you to the GitHub Desktop application, if it asks how you want to "Configure Git," you can choose the default option of "Use my GitHub account name and email address". Click Finish.

Adding repos

If you already have git repos on your computer, you will need to show GitHub Desktop where those files are. Open up a Windows File Explorer window and go to where the repos are. Click and drag the folder containing the repo into the GitHub Desktop window.

In the pop-up, click Add repository.

Repeat this process for each repo.

You can trust the repos. When adding repositories, you may get a popup warning saying something like, "this repo comes from an outside source which might not be trusted. Add it anyway?" This happens because the code is saved to a shared folder on the computer that other users can access. Just click the "trust" or "add anyway" button.