In order to use RTB or register on the RTB website you will need to have purchased a valid copy of Blockland. RTB also requires you to have installed the latest available update for Blockland which you can find here, or by using the auto-updater within Blockland.
If you're unsure about how to install add-ons for Blockland, follow these instructions precisely.
If you didn't manage to install RTB, you can contact support to get more help with installation.
You'll be able to find a bunch of other useful downloads below.