Create an account
An email, a password, and a town.
That is the whole of it. No card, nothing to buy, and no verification email — nothing is ever sent to the address, so use one you will remember rather than one you can prove.
Then what?
Sign in with the same email and password in the Android app and start photographing. Everything you add belongs to this account and to nothing else — and you can take all of it back whenever you like.