Tvheadend

In case someone needs this info...

Although you can add a parameter to point to where the xmltv.xml file is located, the best solution is to put the file where the script looks. Check out the top of the file and put the xmltv.xml file there. Next, go into tvheadend web page, go to Configuration > Channel / EPG > EPG Grabber Modules and find you grabber file. It should be listed as Internal: XMLTV: ...
Select the line and enable it. Next go to EPG Grabber tab. Near the top is a Re-run Internal EPG Grabbers. First, open the log page by clicking the bottom right corner up arrows, then click the Re-run button. You should see the file run and if it ingested a file, then there should be more than zeros in the result. To schedule it to run, go tto the Internal Grabber Settings section on the page and fill in when you want to run it. It follows the crontab format. I use the following

0 6 * * *
0 9 * * *
0 12 * * *
10 18 * * *
53 18 * * *

I also click on the "Force initial EPG..." checkbox. Good luck.