Alright, now is time to prepare the canvas inflation tube for sewing.
First pin the 22" x 216" canvas strip (or equivalent) flatly around the edge of the heart that doesn't have handles on it. Also! Make sure that the part of the valve that you blow into is laying flatly on top of the part of the canvas heart that doesn't have handles. Sew one inch in from the border around the edge of the heart. Once it is sewn, lift the strip up and see if it looks three-dimensional with the handles and the part of the valve you don't blow into on the outside (see secondary image).
If you checked the secondary image you will notice that the strip attached all the way around the border of the heart is not closed on each end. Lay the ends of the strip flatly together and sew them in a manner so that the excess fabric of both ends is facing outwards. Cut any extra fabric that extends more than one inch away from the seam.
The last step now is to repeat sewing the other heart to the canvas border in the same manner as the first. The only difference this time is to not sew completely around the heart. Leave an open gap of about one foot (or large enough to pass your arm through). And don't forget to make sure that the handles are facing towards the outside of the heart frame.