Pics below are my boat before I started the resto, picking it up from the marina. It has the cabin cover that snaps all the way around the cabin roof and down the companion way doors. Mine is very old and probably not waterproof anymore. It only snaps on when the pop-top is closed and snaps down over the companionway, very effective at covering all the teak including the handrails.
If you were at anchor and on the boat at the time and needed the pop top open you'd want the pop top tent. This is made vinyl and has windows, covers the gap between the cabin top and roof in the up position, and also the companion way but has a zipped entry.
If your boat didn't come with them they are expensive to buy unless you can find them used and in good shape. You can also make them if you handy with a heavy duty sewing machine. You'll need the snap bases which screw into the fiberglass of the cabin and down the teak of the companionway.
Obviously the cheapest way is a tarp tent over the boom. I'd recommend finding the white heavy duty tarps because they reflect heat better and seem to stand up to sun better. The blue and brown ones get eaten up pretty quick, especially if you leave the boat covered dock-side or at anchor.
