For this to work you need to run a kernel that has DSA enabled (see raspberrypi/linux#6899). As of this writing only the newest kernel (6.12.34-1+rpt1~bookworm) has this module enabled. In order to successfully build the kernel modules and the device-tree files you need to install a couple of packages:
apt update
apt install linux-headers-rpi-v8 dkms device-tree-compiler
If you are using a CM5 you have to also install linux-headers-rpi-2712.
Now download the deb package from the release page and install it with:
dpkg -i axzez-interceptor-switch-dkms_6.12-1_all.deb
This will build the necessary kernel modules as well as the device tree overlay. The device tree overlay has 4 parameters that allow you to override the names of the 4 DSA interfaces that will be created once the overlay is loaded, i.e. by adding the line:
dtoverlay=axzez-interceptor-switch,port1name=svc0,port2name=iot0,port3name=unused,port4name=mgmt0
to /boot/firmware/config.txt.