Ironing
I have an Easypress now. But I don’t know if you need one for this project. I just used my small iron.
With an iron set and the highest setting without steam, warm the area you are going to put the design on then place the design where you want it. Press fairly hard on the design. Use a lot of pressure. You are trying to melt the material and force it between the fibers. After you have pressed the area, go over the whole design slowly a few times. If it doesn’t stick well try again. If you use glitter vinyl, it is very difficult to melt. This make take a few tries.
After it cools and I’ve taken the paper off, I always repress the design just to make sure it seals. Use parchment paper between the iron and your design.
And your Customized Ear Muffs are done!