Basically you need to log into your simplelogin account (which is automatically created by proton when you sign up) which proton uses to create aliases. There you can configure more email addresses. You can then select those when creating aliases in Proton.
Hi everyone.
I found an answer here:
https://www.reddit.com/r/ProtonMail/comments/15zkc6t/alias_forwarding_only_limited_to_proton_email
Basically you need to log into your simplelogin account (which is automatically created by proton when you sign up) which proton uses to create aliases. There you can configure more email addresses. You can then select those when creating aliases in Proton.