I'm trying to copy a selection from one image layer to another

[jimindt]

I've got an original image of my 1850 great great grandmothers photo. I made a layer copy of  it, made changes on that Layer(2) and made another copy of that layer(3) and made even more changes on the third Layer.
When I  cleaned up the third layer, I took a bit more than I needed to out of it. I want to go back to the second layer and copy a section of it and put it onto the third layer.

I've tried this which I found somewhere:

1. Select what you need - I did this with Free Select on the second layer
   
2. Select - Save to channel. I did this on the second layer
   
3. Ensure the newly created channel is selected and Edit - Copy (Ctrl+C)
   
4. Go to the image where you want to insert the selection (I clicked on the the third layer)
   
5. Open “Channels” and create a new channel (a button at the bottom or via the context menu) - did this on the third layer
   
6. Ensure the newly created channel is selected and Edit - Paste (Ctrl+V)
   
7. Open “Layers” and anchor the floating layer (a button at the bottom or via the context menu)
   
8. Open “Channels” and replace the selection with this channel (a button at the bottom or Channel to Selection in the context menu)
   

Get lost/confused around step 5. What exactly is the Channel doing? If in step 6 the Edit/Paste creates a 'floating layer' which contains the area I copied in Step 1, what exactly is Step 6 telling me/doing as I thought the anchoring of the floating layer (step 7) merged the selected area into layer 3?
In step 8 what selection is meant, and which channel is being referred to as there are two channels?

And with all of that, I still don't see my selection anywhere.

Jim