Diagnosis
You can wall mount it, but Polk didn't include a bracket. You need a universal soundbar mount that fits its size and weight.
How to Fix It
First, measure your Signa S2. It's about 35 inches wide. You'll need a universal mount rated for its weight (the S2 is light, so most mounts will handle it). Look for a mount with adjustable arms or a shelf style. The key is finding the mounting points on the soundbar itself: on the bottom, there are two standard threaded inserts (keyhole slots work too). You'll attach the brackets from your mount to those points, then secure the whole assembly to wall studs.
If That Didn't Work
If you're unsure about drilling into the soundbar, another clean option is to use a floating shelf just wide and deep enough to sit the soundbar on. This gives a mounted look without any modification to the unit.
Heads Up
Leave enough space behind the soundbar for all your cables to bend naturally. Crushing the HDMI or power cable against the wall can damage them over time. Also, if you're using the subwoofer, remember it needs to stay on the floor near a power outlet, not mounted.