CNC files not 3d in preview

I have a blender file that I made into an STL and tried making a CNC job out of it but I can’t seem to get it to show up as 3d in the preview when generating the code. I’m sure I’m just putting in wrong parameters but I’m honestly not sure what to do.

In a nutshell, I’m trying to make a beer glass shaped handles for a kegerator. I planned to use 1.5in or 2in thick wood and would need to drill a 1/2" hole that’s 5/8" deep to put the threaded insert into so it can be screwed onto the keg faucet.

Any advice or help would be extremely appreciated. I’ve managed to do plenty of successful laser and 3d print projects, but never CNC…

Files can be found here: Snapmaker files