Do you mean installing the Foster connector so you can attach the pedal, or the pedal construction itself?
This is the pedal I built: https://www.thingiverse.com/thing:1394639
Adding your connection point can be as simple or complex as you want. If you're the down and dirty type, you can drill a hole offset from the centerline (not accurate), but it won't cross the seam (hah!) of the trap itself, leading to a more secure connection. If you want it centered, I'd recommend reinforcing the seam before drilling.