Also worth mentioning that there are third party 3d-printed mounts that can go on the arms as well, to support various models of lights. I was thinking about getting those, but just haven't spent the money yet. Here's the link to those...
I *think* (based on a screen shot) the OP is using a computer running some version of Windows, but that he downloaded the Mac version of the app. If that's the case, he should stop and start over with downloading the right bits.
Macs don't need...