PS3 not showing on TV

I really need help. I just got a new TV and the screen keeps on showing a window saying "no channels have been added yet. Please go to the install and return to menu to add channels" (I'm currently the UK, by the way, and I was paranoid over the fact some people need a TV license for watching channels but I will only be using this for gaming so I will not need one). Well, I have all my cables connected, and correct (including the hmdi cable), and my PS3 screen is not showing in my TV screen. I did try scanning for channels in the tv and nothing changed (same screen continued), I tried to holding down the PS3 power button with the noises and everything. Still.... nothing changed. 

   What else can I do, or what am I missing? Could it be something with channels that I need to get? (which would make no sense).