Hey Denlin,
If yours is a spouse visa you DO NOT have to register your visa interview online! They only say that because with some visa types you do. But they have already scheduled yours for you. You just need to make the account and then register which location you want to pick up your passport. You will print that and bring it to the medical exam along with your appointment letter, passport, money, and any vaccine cards you have.
Mw swete infomasyon sa ap edew!