Apple-ID email

I have been using my gmail as my Apple ID email. I wanted to change it today and I wanted to get the I cloud email. I signed in with my Apple ID and I discovered that I have created an alias to my gmail (? I guess)

1. How can I make my apple email my main and not as any aliases
2. How do I change emails for my Apple ID account. It says that it "cannot be changed at the moment" and in the description when I mouse over emails it says that my iCloud email is my alias email
3. The only thing that I have done is to go mail -> preferences -> email address -> I removed my current Apple ID one and I added the newly created iCloud address