Hi and thank you for using justanswer.
I`m going to help you with your tv but first i`d have a few questions so please bear with me.
Could you give me the model number of your tv ?
Also perhaps we could setup your direct tv remote to work with your tv.
But i would need it`s model number as well.
It should be written on the back or inside the battery compartment.
Be waiting for your reply.
I looked at your tv and there seems to be a tv/av button at the front that you can use to switch between tv and audio/video inputs.
But you may have to do the channel scan/program.
To do so,press the menu button at the front and select the last icon on the right by using the vol up button,
once you`re there you can use the chan down to first select tv or cable(vol up/down) then scroll down to channel search and press vol up.
This will program all the channels available into memory,including the channel 3 and 4 to connect your direct tv box.
For the direct tv remote programming it would appear that it is built-in your receiver`s menu, you can find the instructions by clicking HERE
Hope this help and feel free to ask any questions before you accept my answer.