Can I Add aMember on to an Existing Forum?

Hi. Pardon the newbie pre-sales question...

I have not yet started a vB forum, but I would like to soon. I do not need
to have restricted membership access yet. (It will come later.)

Can I add aMember functionality to a forum after it is already in existence,
or do aMember and the forum need to be configured together at the
same time that the forum starts?

Thanks.

-- Jeffrey

If you want an idea of the steps read here