Insert four 2.5mm hex nuts into the back side of the Slide bosses.
1) Thread a hex nut just onto the end of a M2.5×20 screw to give you leverage.
2) Push the nut firmly into the hex pocket on the underside of the boss until it seats.
3) A light tap with a hammer may be needed.
4) Unthread the screw and repeat for the other three bosses.
SKIP this step for the Sparkfun/Adafruit Sensor and Circuit Playground Express Click/Slide combinations.