Inline details for custom reports

I am getting started in report generation on satellite and seem to be having difficulty with what should be trivial items.

To facilitate generating custom reports I'm starting with a last_checkin report.

So far I've stumbled on using "Last_Checkin(host)" vs "host.last_checkin" from another post. However, I don't see how I would know about this without asking.

Similarly, I would like to print the report generation time and host filter inline. (Probably as a second table). I've tried unsuccessfully to use "input("Host filter")".

"<%- input("Host filter") -%>" outputs blank
Trying to loop over use ".each" resulted in syntax errors.

So I"m looking at how to get those values printed inline.
Additional I'm looking for reference material / methodology to discover functions similar to last_checkin and better understand general the syntax.