On my other platform, I was able to setup something so that if there was no motion for 30 minutes after 11pm, it would turn off all the lights. Can someone give me some pointers on how to set that up with Hubitat?
If you're opposed to Rule Machine or new enough to the platform that you don't feel comfortable using it, here's another idea: create a virtual motion sensor using the built-in Zone Motion Controllers app. Choose "Motion Aggregation" as the zone type, include all sensors that you want to monitor for inactivity, and choose either the "30 minute" timeout option here or a short timeout and do the 30-minute delay logic elsewhere. Then use a stock app like Hubitat Simple Lighting to turn off the desired lights when this virtual/aggregate sensor goes inactive (either right away or with the 30-minute delay if you didn't build that into the Zone Motion Controller). Set a Restriction on the Simple Lighting app so it doesn't do this outside of your desired time frame.
The advantage of doing it this way is that now you have one sensor you can use in other automations if desired. A disadvantage is that logic is spread across two apps, but there is nothing wrong with that--as people used to say (when Rule Machine was simpler and multiple rules were often needed to achieve a single goal), "rules are free," but that applies to regular apps, too. It's also probably a bit easier to set up, though either isn't bad if you're familiar with Rule Machine.
As with many things in Hubitat, there are often multiple ways to achieve the same outcome. Good luck with whichever path you choose, and feel free to ask anything if you have more questions!
If I want two actions to happen after the 30 minutes of inactivity, (let's say set HSM to arm) doI create an action below it that is also delayed 30 minutes? or does a second action happen right after the first delayed one is executed?
In that case, I'd use an actual Delay action, rather than the delay switch on an action.