Lede / adblock noob

I believe they do update at boot, although I'm not positive about that, if you'd like to update with a daily cron job instead of rebooting, you can just go to System>Scheduled tasks in Luci and enter something like this -

0 3 * * * /etc/init.d/adblock reload

the developer for adblock, @dibdot, is really good about helping and answering questions, here's the thread for adblock help - Adblock support thread

and the wiki for cron that might help - https://wiki.openwrt.org/doc/howto/cron