My rca TV only has 1 coax hole, I have dish receiver that it goes to, I want to add a dvd player with only the 3 rca jacks (red, white, yellow), no coax hole. What can I do to get all three to work together? Thanks.

You should be able to get the needed adapter at Radio Shack or just about any electronics store.
I'm sure the folks there will be glad to help you.

What you need is called an RF Modulator. You can pick them up at just about any electronics store.