While they’re all still in pots, it’s best to water them 2x a day, am & pm. They should have good drainage in a pot, and they’ll need a drink 2x a day in the heat of summer.
Once planted, I would give them an initial good soak (a ‘trickle’ from a garden hose for 15 minutes or so per plant to make sure there are no air pockets around the root ball in your planting hole. If you need to water from a can, give them a gallon of water each, to do the same.
Then - dependent upon rain, treat them like any other planted thing - 1” of water PER WEEK.
Don’t panic if they look ‘droopy’ once planted. It will take a week or so for them to get adjusted, and while you’ll THINK they need a drink - they don’t! Over-watering them will also make them look ‘droopy.’ It’s a vicious cycle! ;)
Also, when planting, make sure you break up the root ball - you may need to score it with a box cutter, which is always my tool of choice for that job. You won’t hurt it - I promise!
Apart from watering and depending on where you are located the standard Black nursery pots they become very hot when in the sun, as high as 135 F, which is hard on roots.
This is not as much of a problem in Northern Tier states like WI. If possible its not a bad idea to put the pots someplace shady during mid-day.
Now heading off to turn on the soaker hoses in the garden before it becomes too warm! (The squash/pumpkin vines are total drama queens and look like they are dying in even sunny warm weather, but they will definitely need it with today's coming heat!)