DDJ-RZ Rekordbox Help

So I just purchased a DDJ-RZ after being a long time serato user and SX user. I have been having trouble learning how to use Rekordbox and the RZ. Specifically I can’t seem to get the RZ to go into External Mixer mode in Rekordbox. I am only able to change it from internal to external on the RZ Sound Utility app. However, on Rekordbox the option for external mode is grayed out. How do I fix this?? Another problem I was having was my right deck (deck 2) was showing the volume lights on the mixer in channel 1. Why is this?