The pH FeatherWing is sold as an unassembled kit. The kit includes the pH FeatherWing v0.2 board (PCB with all of the smt components), and a set of through-hole components. These are i) 3-pin screw terminal connector (blue), ii) 12-pin and 16-pin headers and iii) BNC connector.
Before you can use the pH featherWing, you will need to solder the through-hole parts onto the pH featherWing as shown in the images below.
i) Orient the blue 3-pin screw terminal connector so that the side with the connectors is facing out as shown below.
ii) Solder the 12-pin and 16-pin connectors in place so that the shorter pin goes through the holes in the PCB and the longer pin is exposed as shown in the image below:
iii) Press the BNC connector onto the board and solder in place.