How to setup Hyprlock as the default lockscreen?

I’m using Hyprland and would like to use Hyprlock as well. I looked at the github repo and the wiki page but they don’t describe to how to make it the default lockscreen. I added programs.hyprlock.enable = true; to my configuration.nix and nothing happens when I reboot.

Hello
So hyprlock is only a lock screen. I think what you meant with:

is a displaymanager. There is a difference in those two. A lockscreen is only for locking your session. A displaymanager manages the first login and starts such a session. This is what you properly want when you want it on a reboot. Sadly hyprlock is only a lockscreen and not a displaymanager.
But if you meant how you can lock your hyprland session with hyprlock you can do it with this keybind:

#lock the system
bind = $mainMod, L, exec, hyprlock