How to care for a baby oak tree?

Well, for a start I would rescue at least a dozen just in case one doesn't take. Plant them all in the same large pot. A good potting soil with rotting leaves or compost. They won't survive in the house so place them in a spot with sun and filtered sun. Water when necessary. Let the surface dry but when you stick your finger in the soil you should feel moisture, if not, water them. Don't forget they'll be outdoors so will get rain too.When the 1st frost hits cover the pot with burlap, the leaves will fall just like a big tree but don't water. They like to be outdoors as it's natural for them The burlap stops any snow from crushing them. They are hardy so should do ok. Keep them in the pot for a few years, until they are sturdy enough to plant in the garden. Feed them in the spring with Miracle grow. Good luck.