setting up a new smart tv and trying to connect to an old DIRECTV satellite box

Hello cburchfields, if you have a DIRECTV receiver, you don't need the DIRECTV app anymore. Additionally, if you still have the remote for your receiver, it will function just like a traditional TV remote. You can learn more about setting up your DIRECTV remote by clicking on this link: Set up your DIRECTV remote | DIRECTV Customer Service & Support. Kharl, DIRECTV Community Specialist

Just use the same remote as usual since you're not using a new receiver you're just changing tvs. Is the old receiver standard definition or high definition? 

Note: program DTV remote will not control the smart tv functions.

To use one remote for both, you need a different remote, not DTV remote, and not the TV remote.

Greg