Here's what it should look like when you're finished:
Square holes connect to the Probe
Round holes connect to the Button
Lift the middle tab and solder your favorite button facing down so it can be pressed by pushing on the bar (pro tip: stick something in there to keep it down while soldering)
Break off that triangular tab at the end and solder
it to the end of the wires that connect to the Jumperless.
The 2mm pitch header pins should friction fit into the
2.54mm spaced holes 18 and 19 at the top left corner.
Strip the single wire wrap wire (you can use your fingernails)
and lace it through the holes around the needle tip, then
slide the needle under it and flood the whole pad with solder
Remember to bridge those pill-shaped pads with a tiny dot
of solder at the end of the rows connecting to your button.
If pressing the button puts the Jumperless in probe mode but doesn’t light the LED or sense rows, the Button and Probe connections are swapped, just turn the connector around.
Or just have fun with it and do it however the hell you want! I’m a piece of paper, not a cop.