To activate CBPRESS, download the zip file and and install the plugin from your Wordpress admin panel.
Once you've installed the plugin, you can activate your copy from the CBPress menu using the ClickBank Receipt number from your CBengine order.
CBPress will then embed your own ClickBank affiliate ID on all hoplinks generated by the plugin on your site. You can create a full ClickBank marketplace, or setup custom lists of ClickBank products. CBPress is very flexible!