Very small cattleya orchids dry

[jorged0712]

Hello recently while at Home Depot I saw that they sold little orchids (no flowers) in a little pot in a bag, Better Gro brand. They don't sell cattleyas in the nursery and I've always wanted some so I decided to buy the healthiest one I could find. The problem is that the medium was very dry and they had very bad/dry roots so I had to cut almost all of them off. I re-potted them in Miracle Gro orchid medium and watered them about 2 days ago but their roots seem very dry and white. I was wondering how can I keep them from dying. I've never had cattleyas. How often should I water them? They're very small.