How do you get a 7 set cascade in bejeweled 2?

In an OurWorld Challenge, I had to make a 7 set cascade in Bejeweled 2. Follow these steps. (It might sound easier than it really is.)

1. Make an Orb. (Connect 5 Jewels to make an Orb.)

2. Swap the Orb with the Jewel type that most covers the area.

3. Once you've done that, hope that you get a 7 set cascade!!