There are 3 available login methods that you can use:
1. Continue with Google account: Will use the information you have used when you signed up for your Google account.
2. Continue with Apple account: Will use the information you have used when you signed up for your Apple ID.
3. Register using your details (eg Name, Email, Date of Birth) and nominate a password.
Please note that you should only pick 1, and keep on using that, as using another method afterwards will create another account that might revoke your access to the site.