Here is the life of one tray that has started indoors but has been moved in the garden (I keep water play and messy play outside, even playdough, because I have a toddler):
I like to let the kids build their own tray, after you showed them what can be done.
Remove the edible sand, put it in a bag and store for next time. Scoop most of the blue sand to keep but don't go crazy - leave some, don't hoover or kill yourself sweeping. Next: put biogel balls (you will get the best results if you make them overnight?) and add water. Add scoops and cups and everybody is happy again.
Move the playdough but don't bother cleaning the tray from the sand, glitter and tiny biogel balls. Make jelly baff with your kids. Give them whisks and spoons, they will enjoy it. When the jelly is done, put whatever shiny kitchen utensils you have, plus some pots and bowls.
Look at your amazing effect!!! Well done!
I'm afraid that you will need to clear up all that jelly when they get bored. It is actually not that difficult once you add the dissolving powder from your pack. It will turn into water.
P.S. The jelly gets really slippery once on a hard floor, so please be careful. Outdoor use is the best.