Magnetize your infantry bases for Conquest.  The holes accept 5mm diameter 1mm thick magnets. The holes are designed on size so they should press in with medium effort depending on your print settings. 

When initially installing magnets into the tool, make sure to keep their polarity oriented in the same direction and that it matches the polarity of the Tray Tool or it won't work properly. 

Once the magnets are installed in the tools, place the infantry bases upside down into the cutouts. Dab a bit of your favorite adhesive and place a magnet on the center. The magnets will center and fix their polarity to match the ones in the tool.