get some smallish treats, but high value - like bits of hot dog, give her a couple so she knows what they are, then start throwing them onto the bed so she has to just eat from it, then eventually stand on it to get them. If you get all four paws on, just feed her on the bed and see if she will sit/down for the treats. Could take a few attempts.

If she is more toy than food oriented - same thing but with toys.

Also - remove the old bed then there's no choice!