Arduino, XBee and Redbot Mainboard

I’m trying to figure out how to use an arduino with an Xbee shield. I connect one Xbee (Both Series 1) to the Arduino + Shield, and the other Xbee to a redbot mainboard we are using to control an RC car wirelessly. However, whenever I try to find the Xbees using the XCTU program, it doesn’t find them? What can I be doing wrong? I’m pretty new to Arduino and this is my first project.

When you plugged them in, did your OS automatically install the drivers?