requires as a prerequisiteBrowser Info Environment
I can't install the package, het the following message:
Installation requires as a prerequisite that Block Designer is already installed.
Please help me out.
I assume you figured out what to do, right? On the Block Designer Pro page it is mentioned a couple of times that you need/require Block Designer first, as this is the base of the product. Block Designer Pro adds an aweful lot of extra features on top of this base.
As I see you've purchased Block Designer too, install that first, then install Block Designer Pro.
If you still have questions, do ask!