i used to have 3 golden apple snails (and 1 blue one) and they would constantly mate and lay eggs above the water line. I would sometimes save a few large clutches and wait weeks for them to hatch but they never did. Here are some tips from a fellow user gena575 on apple snail egg care:
"Yes you can leave them where they are. You could also gently remove them and place them in a diy hatchery if you are a control freak like me My diy hatchery consisted of 4 strips of styrofoam and a square of plastic craft canvas siliconed together to make a little clutch raft. (
www.applesnail.net has lots of ideas in their DIY section) I floated that in a lidded square tupperware. I put that on my light strip so it would stay nice and warm. It took from 13 days for them to hatch IIRC. You'll notice a moldy gross look to the clutch when they are nearing hatching. Ah heck, lemme just post some pictures This clutch was mailed to me so it is 2-3 days old in the first pic."
The DIY nursery
Here the clutch is 11 days old and near hatching
Hatching in progress
The resulting baby snails
Hope this helps. I love apple snails and Im probably going to get them again in the future. Good luck!