You may be more advanced with 3D coat and want to pick up some of the finer points from a video, but I'm going to type this anyway because I was very stuck trying to bake a normal map and get my unwrapped object from the retopo room to the paint room.
The basic process is simple (but fairly non-obvious because menu item is buried and cryptic and surrounded by similar sounding options).
Anyway, once you have your UVs marked and unwrapped in the retopo room, select "Merge with NM (Per Pixel)" from the retopo drop down menu. Click ok when the dialog box comes up. Click ok when the next dialog box comes up. Go to paint room. Your model will be there. Paint it. Your normal map will be on one of the paint layers. Your UV will be available in the UV room. Your 3D life will be good.
Sometimes your vox model will still be visible and cluttering things up in the paint room. Turn it off by going to view menu and unchecking "show voxels in paint room" (or as an alternative, hide everything in the vox tree).