I know it looks daunting, but it only takes a few times and you will be doing this in your sleep.
Step 1
Duplicate the element (ie ribbon) and place duplicated layer under object to be woven around (ie frame)
Step 2
Ctrl+click on the thumbnail of the frame. Marching ants will appear around the frame
Step 3
Move your cursor to highlight the top ribbon layer. Then use your quick selection tool. Make sure it's on subtract from selection.
Remove the marching ants from the parts that you want to keep on the top of the frame. Only the part of the ribbon that will be "under" the frame should have marching ants now. Notice you don't have to be neat - just make sure that the parts you want erased are selected.
Step 4
Press Ctrl+x or Delete to delete the parts that are on the top that shouldn't be
Step 5
Shadow the bottom ribbon only. I use a drop shadow action. Don't forget to shadow the frame too.
You can use the burn tool to add a shadow under the top ribbon over the frame if you think you need it. There is a more involved way of shadowing if you have clusters of flowers and stuff on your ribbon. I'll leave it at this though so it's not overwhelming, but let me know if you want those instructions. I hope you find this tut easy to use!