Moving right along.  

Now we’re working on the inside of the coat.  Take the larger pocket piece and align it with the other piece of pocketing.  While doing this,  smooth the pocketing and the coat fabric flat.  Pin the pocket bags together, but BASTE the the upper pocketing to the coat fabric above the welt opening.  This will hold the pocketing in place for the next step.  I’m a “baste-a-holic” so I would probably baste the entire pocket assembly to the coat front.  

Now from the outside of the coat, edge stitch along the fold where the fabric was slashed and pressed back.  The basting will help hold all this together and keep things flat.  This will secure the pocketing at the opening of the pocket.  

Now stitch around the pocket bags to complete the inside.  

The welts are then pressed back into position and stitched down.  I hope this has been helpful.  I know I’ll be more confident when it comes to working on the real coat.