Hi, If you are still looking how to do this:
You will need to go into and edit the BP_Desktop_FlyMode_Pawn found in CollaborativeViewer>Blueprint>Pawn>Desktop
In there you will need to select the CapsuleComponent, and then edit its collision preset from none to pawn.
See image, I hope this helps you. It is great to use with blocking volumes so they are limited to where you want them to be.
