Tvheadend

Hi all
I wanted to configure a tvheadend server an my raspberry pi to stream IPTV to watch it in my PS3 because the PS3 is in a room where no tv cable is accessable and my RPi is running anyway 24/7.
So I downloaded and compiled the tvheadend on the Pi and i can access to the web interface via IP:9981.
But I can't get any TV channel running. I got different IP adresses for channels (e.g. on http://www.onlinekosten.de/forum/showthread.php?t=125563) and added them in the web interface at the IPTV register. My Pi is normally connected via a WiFi Ethernet stick, but for setting up I also connected it per ethernet cable (because you cant connect to the RPi vis SSH by Wifi) so I inserted the channels double, once with interface wlan0 and once with eth0. The channels appear in the channels register/tag but when i click play the vlc web plugin appears, but I just get blackscreen, also no sound. I also created a dummy user at the register access control, I inserted the IP of my notebook (without port) checked the tag"streaming" enabled it and saved, but still no channels running.
I also installed the htsp plugin for my vlc player and inserted the RPi IP in the settings and set the port to 9981 (standard it was 9982). I inserted the dummy user and pw, also i tried with the administrator username and pw, but when I go to playlist->tvheadend htsp, no channels appear.
When I open a network stream with http.//IP.OF.RASPBERRY.PI:9981/playlist, the inserted channels of IPTV get listed, but when I want to play, still only black screen and no sound.

How do I correctly setup the tvheadend to stream the channels (e.g. from the link above)?
And what is wrong with my vlc plugin not getting the channels by playlist->tvheadend htsp?

Also I found this page
https://tvheadend.org/issues/1137
to import the channels from a m3u file, but I have no idea how to do this (I am a linux noob)
I guess i have to run it on the RPi but I have no idea how to enter in the shell.

It would be really nice if someone could help.
Thanks