Hey Adriansnetlis,
Are you not able to go [here][1] and click on ‘Get UE4 Full Source Code’ where it says ‘[Learn about linking your Github account][2]’ to download the UE4 Source Code? Because if you can get there, all you need to do is create your account at GitHub.com, then go to your account and associate your GitHub username with your UE4 account.
The website is showing an error currently, but that is a known issue which we’re looking in to. It should be fixed shortly. Please respond here if you’re not able to attach your GH account to your UE4 account by tomorrow.
Thanks!