Allods Online accounts are directly tied to gPotato accounts. You need to use the same information to log in to Allods Online that you do to log in to your gPotato account. If you do not have a gPotato account yet, you can create one here.
After you create your gPotato account, you will be sent a confirmation email. After following the confirmation link, your account will be ready to be used. You can then use your gPotato account information to log in to Allods Online.