add a second apple tv

If you have a weak Internet signal in the other room, sure you can add an extender. However if you have a strong signal, on extender is not necessary. I have 4 Apple TVs in my house and all work off of the same Internet signal. As my house is long and the router is on one end of the house I had weak signals on the opposite side of the house. I tried an extender however it was inadequate for my needs. If you run into a similar situation you should look into installing a Mesh Network into your house. I ended up with the Google Mesh network, it has been working flawlessly for months.