Help filling "bubble"with clouds

[ni$mo350]

(see link) I'm stuck on step 7. I have the person and shadow on the proper background but I don't know how to get the clouds to fill in the bubble. I made a new layer and filled it with clouds but now it's telling me to go to the Path's Palette and create a selection from the path and mask the layer. I'm sure it's a simple solution I'm just getting frustrated with it. Any help would be appreciated.

Create a Powerful Mental Wave Explosion Effect - Psdtuts+

 

[Nomission]

Have you completed step 6?
Do you have your circle-thing path?
If so...
"go to the Path's Palette and create a selection from the path and mask the layer"
Better yet, with the direct selection tool, right click the path and choose "Make selection".
After that, select the clouds layer and add a layer mask. That's it.