Is there a way to create a new account on waellet or do I need to import an existing seed phrase or key?
You can create a new account of course.
If its your first time opening the waellet you will be presented this screen:
You can generate new keypair clicking Generate new wallet.
Otherwise if you already have an account logged in you can clear your browser memory (keep in mins you are going to loose the current one if you haven’t saved your seed phrase or exported your private key somewhere) and generate an account all over again.