As you have noticed from the previous post I haven't finished the background, I decided not to stitch it and leave it blank and framed it the way it is.
For backing I used a white piece of fabric. First I laid down a stitched piece on fabric to get the feeling
I used Wonder-Under paper to attach the stitched pieces to fabric. I cut a needed size of Under-Wonder paper, laid it down on my piece of fabric with paper up and ironed it.
Then I carefully took the paper off
After that I laid the stitched pieces down on the piece of fabric faces up
Covered with another piece of fabric and ironed it again.
Now, when my stitched pieces are attached to the piece of fabric I tried the frame centering the design
I cut out the desired size, attached the stitched pieces to the backing and then to the frame and here is the finished pieces: