Start by putting the Pro Trinket and the PowerBoost 500 Charger into the enclosure. Use a M2 screw to secure the Pro Trinket. Gently push the PowerBoost into the cavity to fix it in place. It should be more or less a friction fit.

Push the SPDT switch into the cavity at the top of the enclosure, and the pushbutton on the right side of the enclosure. You should be able to see the pins of the switch and pushbutton on the inside of the enclosure.

Use three short wires to connect the power lines between the PowerBoost and the Pro Trinket.

Pro Trinket --- Powerboost

• BAT --- +
• G --- GND
• BUS --- USB 

These connections allow us to recharge the battery through the micro USB port on the Pro Trinket in addition to the one on the PowerBoost 500 Charger, and have the Pro Trinket powered by the boosted 5V source from the PowerBoost. 

Then use two more short wires to connect the reset button to the Pro Trinket. 

Connect the RST pin to the left side of the pushbutton, and one of the GND pins to the right side of the pushbutton.

Now connect the EN and GND pins on the PowerBoost to the left and middle pins on the SPDT switch. Be sure to run the wires on the side instead of going straight to the switch. We want to leave some space for the LiPo battery.

Finally we can connect the battery to the JST connector on the PowerBoost to test the circuit. If you slide the SPDT switch to the right, the boost converter will be enabled, and the system will power on. Make sure that you see both the blue LED on the PowerBoost and the green LED on the Pro Trinket light up. 

Also, you can test the reset button as well by pressing the pushbutton and see if the Pro Trinket reset itself.

If everything is working as expected, we can move on to make the connections between the top and bottom half of the Tiny Tetris.