Summarize:

If you want to make your fabric a particular size, place the vinyl over an object that’s as large as you want it to be. If you’re stretching vinyl out for a specific reason, such as to reupholster a piece of furniture, place the fabric on top of the object in question. If you’d like, you can place your vinyl over the object in question before heating it up. To stretch out your vinyl, grab 1 end of the fabric with your fingers and slowly pull it toward yourself. If you’re working with firm 2-way vinyl, feel free to use a lot of force while pulling. If you’re stretching thin 4-way vinyl, pull carefully to avoid tearing the fabric. If necessary, hold the other side of the vinyl down with a bar clamp or ask a friend to keep it in place. As your vinyl stretches, it may develop small, unappealing wrinkles. To remove these, simply press down on the fabric with your fingers and smooth them out. If you’re stretching the vinyl over a specific object, make sure to press out any creases or air bubbles that form. Over time, your vinyl will cool down and become harder to manipulate. If this happens while you’re stretching it out, grab your heat gun and run it over the material again. Do not press your heat gun to the vinyl fabric. If you do, you may damage the vinyl itself as well as the material underneath. If your vinyl starts to overstretch, make small incisions along the edges of the fabric with a pair of scissors or a precision knife. This will give you the ability to pull on 1 portion of the fabric without affecting the other parts.  Only use this technique on pieces of fabric where the edges won’t be visible, such as vinyl upholstery. If you’re pulling the vinyl around an object with curves, you may need to cut the fabric to help it better fit the object’s shape. If you’re using your vinyl to reupholster an object, you’ll need to secure the material to keep it from peeling off. To do so, pull the fabric as tight as you can and hold it down to the object. Then, use a staple gun to shoot staples into the vinyl fabric.  Place staples between 1 and 2 in (2.5 and 5.1 cm) apart around the entire perimeter of the object. When finished, you should have a long line of evenly spaced staples. If necessary, ask a friend to hold the fabric down or use a bar clamp to keep it in place while you staple it.
Place your vinyl over the object you're upholstering, if applicable. Stretch the vinyl between your hands. Press down on the fabric to remove wrinkles. Apply additional heat if the fabric stops stretching. Make non-visible cuts along the edges of the fabric if you overstretch it. Secure the fabric with staples if necessary.