Question about swimming pool vacuum hookup?

The vacuum is usually attached with a plastic adapter that sits in the "overflow" opening. On my above ground pool, I had to remove the leaf basket to get a good seal. make sure the hose is filled with water before attaching it to the pool so it isn't sucking air.

If you have a sand filter, and the sand in your pool is from the filter, you probably have a cracked manifold or displaced joint in the piping inside your filter. If this is the case, you should probably get that fixed first. You can possibly do this yourself, but it involves removing most of the sand, and holding it somewhere so you can reuse it. Handle the sand as somewhat biologically hazardous - it's typically loaded with stuff you don't want to ingest or get into cuts in your skin. At least use a hand sanitizer afterward. You didn't specify the reason you can't or don't want to use your pool vac system, and obviously I'm not the only one who's curious about that. If it's filter sand in your pool, and you remove it other than through the filter, you will have to replace missing sand in your filter, or else your filtration won't be as designed. As far as alternate methods go, a siphon (with either a vac hose or garden hose) is as cheap as it gets, but with low suction compared to a pump, and everything has to go to waste, which must then be made up. You can also get a portable pump with a strainer and cartridge filter, to perform the same vacuuming as your pool pump and filter, and returning the effluent to the pool or to waste. These cost several to many hundreds of dollars.