Butterflies generally don't eat for one day after eclosure. On the second day, they'll need fresh flower nectar from Milkweed and other plants.
You can also set up a makeshift butterfly feeder with a plastic kitchen scrubber in a bowl of either sugar water or Hummingbird nectar.
This will come in handy for rainy days when release is not recommended.

John

Congratulations on the new butterflies! Listen to Leafhead/John. He knows of that which he speaks. LOL. Happy Fouth to All!!!

Martha

I love you Leaf! Where do I place those things? Does it matter? On some kind of platform near the top? Or can it be placed on the ground? And do they need shade from the sun? If yes, how much shade? Thank you alot! And same to you too Doc! Lol

You can place a pot of live nectar-providing flowers or a vase of cut flowers on the ground in the enclosure. Live, growing flowers will be able to provide more nectar, but fresh cut flowers can be adequate. Shade will protect the enclosure from getting too warm. If it can be under a dappled shade tree, that would be perfect. I usually keep mine in total shade for my own comfort and protection, though they might not be as active.

Martha

What about the home-made butterfly feeder thing? Does it havfta be on a platform? Platform near the top? Does it matter? Thank you!

I don't think it really matters, but you can always be creative, and an elevated feeder may make them feel less vulnerable.
Are you raising Monarchs to lay eggs in your enclosure?

John

Yay got your response before I went to sleep. Again thank you. I'm not. I have yet to do such a thing (eggs thing). Hmmmm I should do that (the elevated platform thing).