Brian,
The two drawing are in the instructions and the photo of the engine used in the Flyer. The "feet" are what the engine rests and are used to attache the engine to the wooden mount ("logs") that is part of the wing structure. drill out the lugs on the engine and match drill in the correct location/orientation on the engine mounts. I'm guessing there is hardware provided to install the engine.
This build thread has a lot of helpful photos including the engine installation the should be of some help.
Here are some pics of the Wright Flyer. This build reminds me a whole lot of building r/c planes. The details and parts are amazing. I haven’t veared from the instructions other than some wood stain. It probably would have looked great being entirely the lighter color, but I like the ribs detail...
cs.finescale.com
Regards,
John McMakin