I cannot control the volume of the tv with the tablo remote
The Tablo remote uses CEC to control volume through the HDMI connection. You need to make sure the TV’s settings allow CEC control of volume. It may be under different names. Or the TV may not support it at all.
Where did you get a Tablo remote? I just always use my Roko remote and then need to use my TV remote for volume.
My installer never showed me any Tablo remote so maybe they forgot to include mine.
I may be glad though that I do not have one as that is one less remote I have to misplace and instead just have the 2.
Remotes are for the HDMI connected units. Not the network unit you use with your Roku.