You have a row of GPIO pins on your uC. You can put a servo control signal out on each one. But then you have to connect that to a servo and provide motor power.
Before, the options where, take up 3 rows on the bread board for each servo and try to find extra long header pins, or undo the header on the servo connector and stick wires in the end (which move around, short, or fall out), or buy a big expensive "shield" or other full sized adapter.
This little board takes up no extra space, ties into the power rail, provides a little terminal block to screw in wires from a battery pack, and most importantly, provides a mechanically stable place to plug in servos.
1x4 pin headers
1x5 pin header
2 pin screw terminal block, 0.1" spacing (optional)
e.g. TE Connectivity 282834-2
NOTE: Trim the ground header really short on each end if you need to use the power rail headers that interfere. Then after soldering clip those short.
Put the servo header rows into a breadboard upside down, then put the PCB over them (again upside down, the servo headers go on top of the PCB), and shake it a bit to level it all out. Solder one pin on one row, check it's flat, then solder the rest.
Solder on the signal header
This goes on the bottom.
Solder in the breadboard power rail header(s) (optional)
Install the board with the signal header down into the breadboard and look through the holes over the power rail to see which ones line up. Pull it up, insert 2x1 pin headers in those locations (or location) and then put the PCB back down and solder the other side.