In this article, you'll learn how to install the Anti-Splinter on the DCS334.
The Anti-splinter insert should be installed into the no-mar shoe cover. All you need to do is slide it into the no-mar shoe cover space, and it'll lock in place. You'll get an audible click when it's properly inserted. To remove it, just pull it the same way you pushed it.
The manual mentions that if the no-mar cover is not used, you can install the anti-splinter insert into the shoe directly. However, if the no-mar shoe is not in use, the Anti-Splinter won't lock in place and will fall once you start using the tool.