U-verse channel

Unless you're using a super old TV*, you can use either HDMI or component connections.  Depending on how YOU decide to connect the box to the TV will determine which option you press on the TV.  For example, you've got a HDMI wire that you choose to use.  You connect the HDMI from the box to the TV.  When you go to "input" on your TV, choose HDMI.  There could be HDMI 1, HDMI 2, HDMI 3.  Choose the correct one.  If you connected the Uverse box using component, your TV input should have that option.  Choose "Component".

When using component or HDMI connections, there is no need to choose a channel to have the TV set on.  HDMI and/or component overrides that issue.

How old is the TV?  Do you have the option of HDMI or component in the back of the TV?  Do you have the instruction manual that came with the TV?

Please note:  I've had Uverse for over 10 years with 3 TVs hooked up now and 2 old TVs that I replaced.  I've replaced probably 3 boxes so I've done this a time or two.  Trust me, it ain't rocket science.

*Edit:  If using an old TV that only has a coax connection, then the TV should be on Ch. 3 according to THIS   Bear in mind that you cannot receive HD channels with coax.