Installing ATLauncher

Go to the ATLauncher Website and click "Setup" under the Windows category.

Run the executable file you just downloaded, then make your way through the installer. Once the installer is done, run ATLauncher.

Once you're in ATLauncher, go to the Accounts tab.

Click the "Login with Microsoft" button and follow the instructions it gives you.

You're done! See Installing the Modpack: ATLauncher for more instructions.