This is where things get fun.

Placing your shield on the fabric so all sides can be covered, pick a starting point and begin stapling your fabric down. I always try to start with one of the largest surfaces, because it ensures that the fabric is stable while I'm doing the rest of the shield.

When you're stapling, you simply want to fold the fabric over, nose the staple gun up against the foam, and plant your staple. I space my staples 4-5cm apart, and generally work from the corners, into the centre of the fabric, but go by feel for what works for you. Don't worry about making sure your fabric is tight for this first side. You want that staple as close to the foam as possible because it will secure your fabric better and, in the event that one of your staples pushes through the board for whatever reason, it will be on a part of the shield that is highly unlikely to have contact. Still, it's worth lifting your shield up to check that you're not having them protrude.

You may have a misfire where one of your staples isn't sitting right. Depending on the situation, either pull it out and put a new one in, or make judicious use of percussive maintenance (see: hit it with a hammer).

When you've completed that first side, you're then going to go to the opposite side of your shield, and start there. At this point, you're going to want to gently tug on the fabric so that it's lying flat against the table/surface you're working on, rather than wrinkled or gathered underneath. Working out the tension of your fabric can be a little tricksy, so I've included a photo of how I pick it.

What you're looking for is, when pulled across the foam, the fabric making a taut bridge between the foam and the wood. Not so taught that you can't push your finger into it, but definitely not floppy. It should have gentle give to it, as we're going to use the other side of the shield to add proper tension If you over-tighten it now, you're going to have a very uncomfortable shield later. Don't let go, simply push your staple gun into the fabric, butt it against the foam, and fire.

If you've ever stretched a canvas before, this is a very, very gentle version of that. What you'll notice is that, in the areas between your staples, you will have fabric pulling. You may want to add more staples accordingly.