Adhere the foam like in the picture, except slightly further apart. In hindsight the foam pieces in this up button were placed too close to the center making it more difficult to register a hot dance move.
Depending on which way seems easier. The top pad can be glued to the foam completing the sandwich or the wires can be foil taped to the pads. Given patience for the sandwiches to be made they were done first in this project, but doing the connections first is also valid, particularly for one with big fingers.
Foil tape will be used for this because of its conductive properties. Poke a pin hole in a half inch tear off, of tape after peeling. Push wire through this hole so that the bare wire gets stuck on the adhesive side and insulation is on the shiny side. Secure the insulation to the shiny side with another smaller piece of tape. Now stick that little electrode on the edge of one of the foil pads.
So long as all the pins go to a separate button this should come out right. Its a simple circuit. Resistance is handled by a pull-up on the Bluefruit chip.