Bought Steinberg's Colliding Worlds - where is it?

That’s fine.

But you can still try to download it from Download Assistant in the meantime. You need the GA5 version.

Double click any of the vstsound files to register them.

You will also need to activate the license. You should have an activation code or download access code in the confirmation email. If it is an download access code enter it in Download Assistant and it should generate an activation code for you. Use the activation code to activate the license in eLicenser.

Otherwise it will not show up in GA. (It should still show up in Library Manager even without activated license).