Ear strap length will depend on strap style. These 4 straps that tie around the ears are 7.5” long. 4 straps that tie behind the head approx 14” long. Fixed ear loops around 5”.
Cut out the pattern adding 1/4” seam allowance
Sew along the curved front edge for both the mask front and back
Iron the seams flat
Pin the straps as shown
Lay the back on top of the pinned straps, seam side facing out
Pin the mask together so it doesn’t shift while sewing. Start in the middle, aligning the center, and work your way out
View of other side
Sew around the perimeter of the mask, 1/4 inch from the edge. Leave an opening to turn the mask inside out. I leave the opening between the straps
You can leave the side slot open to insert a filter or sew closed
Press the mask and knot the strap ends to keep from fraying. Done!