Tvheadend

Hi guys, I can't found some tutorial, about how I need push the IPTV signal into tvheadend.

I has many native mpegts into multicast IP and I'll like to ingest this into the platform to record and watch.

in other cases I need do the same but using UNICAST, example into some media servers I can push the file with this command:

avconv -re -i stream.ts \
-map 0:0 -map 0:1 -map 0:2 -map 0:3 \
-c:a:0 copy \
-c:a:1 copy \
-c:s copy \
-c:v copy \
-f mpegts http://server/live/stream/mpegts

some advice will be welcome.
THanks
Alejandro