We suggest you get the UKSM enabled kernels from 3rd party build services or kernel forks: e.g. Arch AUR, pf-kernel, zen kernel, etc. Some of the binary builds can be found in the download page of this site.
The installation steps for various Linux distribution are the same with their official kernel install documentation.
After you installed the kernel, reboot to it. If you can find the UKSM sysfs directory “/sys/kernel/mm/uksm/” , then it’s a UKSM enabled kernel. Otherwise, please check the installation process (e.g. grub entries).