Keller Jig.
What you've got there is a

rip-off(?) of the Keller Dovetail Jig, which has been around a while. :furious:
The instructions are those for the Keller Jig.
And yes, it is the complete core of the jig - the mounting board is to be supplied by the user, if you buy it from Dave. The clamping is up to the user, although Dave has suggestions.
You have the BIG dovetail model. The Keller jigs also make nice box-sized dovetails.
I should know: I've had a Model 1500 for several years and think nothing of making dovetailed joints for almost anything. It is a pleasure to make them - something I can almost do in my sleep.
You can search YouTube for Keller Jig for some demo's.
It's my guess that your gift-giver obviously didn't know too much about woodworking, in as much as they bought you a big model.