Follow the Arch wiki. Just make sure that your distro has a hook for the package manager for signing the kernel. Eg. for Arch there’s the systemd-boot-pacman-hook aur package.
It’s not hard to set it up with a LUKS-enabled system, just put the relevant kernel parameters in your /esp/loader/entries/entry.conf file.
For example, here’s my arch.conf entry (with LVM on LUKS):