If the pots they are in are a comfortable size for how big they are you can leave them as they are for the time being. They can be moved into bigger pots when necessary. Strictly speaking potted plants can be put in the ground any time but if that's what you want to do I'd wait until the weather improves.
To get fruit on your Red Delicious you will need another tree of a different variety which flowers at the same time. If you look up Red Delicious apple pollinator you should find lists of suitable ones. If you have only just bought the trees you might be able to swap one of them for a pollinator.