How to use network patch panel in new house
From this photo:




Cable modem is likely attached to the cable at the lower right corner.
Cable modem network jack goes to the internet port on your router.
Lan ports on the router are connected to the patch panel in the center.  The yellow cat5/6 wires are networking to the rooms.
If you want TV's in different rooms, you can swap out which white cables are plugged into the top splitter (or get a different splitter with more ports, but the fewer times you split the signal, the better the signal is). The bottom splitter is the first split to the cable modem to give it the best signal. Yellow cable line is most likely the source, and white cable lines go to the various rooms.
Blue wires should be for telephone. I don't see where the external connection is, so if you don't have a dial tone, it may not be connected to the demarcation outside. If that's the case, either the last owner never used it, or they plugged in a voip box into a network and phone jack elsewhere in the house.