Tvheadend

Sorry if this is old hat for some of you. I am trying to add channels from two different Schedules direct lineups, and the more I read, the more confused I get. I live in between two cites, and one zip code doesn't generate a complete line up for all the stations I receive. I created two line ups Schedules Direct, grabbed them both, and tried merging them into one file. I still don't have the stations from one of the line-ups available to assign as an EPG grab source. I tried hand adding just the channels I need into the bottom of one of the tv_grab_na_dd files and re-pulling the info down. I get the channels that are assigned to the line up on SD but not my additions. I've been at this all week, and now I've read so much that my head is spinning. What's the best way to accomplish this?