Hey Lite5h4dow-
After associating your GitHub account and your Epic Games account (step 2 of the link you posted). You should get an email from GitHub on the account that you signed up to GitHub with. Following the link in the email should take you to a GitHub page to join the Epic Games repository where you can download the source engine. If you do not see an email with the subject of “[GitHub] EpicTeamAdmin has invited you to join the Epic Games organization” then you can follow this wiki tutorial to confirm that your Epic Games account and GitHub account are associated correctly:
Cheers