Vanda orchid with many old roots - what do I do with them

[Sweet mango]

Hello, I'm Sweet Mango, living in Florida. I received a Vanda orchid for Mothers Day. It was in a glass vase, instructions were to water it for 30 minutes and then pour the water out. The orchid did not fair very well. I started spraying the roots until they turned green, every day, and it seems to have helped it. Some of the roots are in a ball and look to be quite old. Some are very long and thin. I would like to know if it is ok to trim the old stuff off, and trim the longer ones back a little.