Step 5: Putting it all together
Finally! Take the larger lining piece and pin it to the right side of the mask’s front. Stretch both lining sections to make the front pucker a little . This will help the mask hug the face. 
Pin the lining bottom around all 4 sides. Easing the cotton front as you pin . See next picture. 
Flip over and trim excess fabric 
Stitch all 4 sides. 
Trim seams slightly and clip corners . 
Zig zag all around those inside seams 
Turn right sides out. 
Use blunt scissors to gently poke those corners out. 
Pouch is created so that various disposable filters can be inserted 
FINAL step : top stitch on the right side to hold the lining in place. 
The Littlest Jockey 