This first circuit diagram contains all parts mounted on the bottom half of enclosure. The JST connector on the PowerBoost 500 Charger goes to the LiPo battery, which is not shown in the picture. The four wires that connect to the 16x8 LED Matrix Backpack are the only ones that connect between the bottom and top half of the enclosure.
The second circuit diagram contains everything mounted on the top half of the enclosure. This is a view from the inside of the enclosure, which means that both the LED Matrix Backpack and the joystick are facing away from us. If it seems confusing, the assembly guide on the next page will definitely help you understand better. All seven resistors shown in this circuit diagram have a value of 10kΩ.
At this point, you might be asking why we're wiring the buttons to the LED Matrix Backpack instead of the Pro Trinket. There are a couple good reasons why we're doing this. One is that we don't need to connect so many wires between the top and bottom half of the enclosure, which makes the assembly much easier. But the underlying reason has to do with the HT16K33 chip located on the LED Matrix Backpack. Let me explain more on the next page.