They will need more than one light coat before you start sanding. For example on the camper floor, after one coat with a roller there were still some areas that showed bare wood due to the surface tension of the epoxy.
This was after the second coat before tipping with a foam brush.
Then when you sand it you are looking for a uniform Gray/white surface without sanding too far. The appearance will go in stages as you sand, from small white spots which develop into larger patches of white and then finally isolated pockets of dark in a sea of white. See below. These areas that are dark are valleys in the epoxy. Depending on how deep the valley is, it could be filled in with a dab of resin then sanded flush. If the valley is shallow enough than the future coats of clear sealant and sanding will level it out.
