buying stuff is slightly confusing but not really

I want to buy the P3d or liardking or whatever its called to make games, but when i went to the clickstore i couldnt login with the same email and password, i dont know if you use a different account for buying that has nothing to do with my normal forum acount. Basially do i need to use the same login to buy stuff for my etensoin managerv or can i use whatever i want?
I don't think id have to since i bought fusion before having an account but i want to be sure i dont waste money
Thank you for reading :)

Seems like you got this sorted X)