Start by grabbing the blue terminal blocks. Terminal blocks only come in 2 and 3 pin sizes, but can be slid together to form longer strips. Start by connecting a 2 and 3 pin piece together. There's nubs on either side so line those up and you'll be able to slide them together
Keep sliding more 3-pin blocks on until you get a 2-pin block with four 3-pin blocks in the middle and then another 2-pin block at the end
Make two of these long strips
Flip over the board and solder in all of the terminal block pins with plenty of solder
Be sure to solder all pins for reliable electrical contact.
(For tips on soldering, be sure to check out our Guide to Excellent Soldering).
Next up place the 12-pin and 16-pin headers in the center part of the breakout in the outer-most set of holes
If you have a Feather, plugging it into the headers will keep them nicely aligned so you dont need to tape them in place
If you'd like to install the slide on/off switch, snap it into place at the end of the PCB and tape it down so it doesn't fall out when soldering
Solder in the two large mechanical points and the three signal pins in the center
That's it! You're done