Two things here. Once when you purchased a LICENSE we send you access details to sign into the members area and download the code. If you want to participate here you need to register a user and password and this thread should assist you with verification.
Next as far as vb3 if you have installed correctly answering all the install options correctly you would login and when viewing your new gallery there is an admin link on the photopost navbar. So we need some more info here. Are you able to login and see an admin link if so click that link and your in admin for photopost. In order to upload etc you must set permissions so while in admin check out the link for edit usergroups. You can set permissions there and once you do that you can upload.
If there is anything else we can answer let us know.