Permit me to reply. I doubt that that configuration is of use to you.
Roku connects to the TV via HDMI. The Roku stick has the HDMI plug on it
Then the Roku (or Roku Stick) also has to connect to the Internet (more on this later). Then you can install streaming apps on the Roku to obtain content over the Internet to stream to your TV.
(aside: Some new, so-called "Smart" TVs also can connect to the Internet and then they have similar apps natively on them that can provide the same content)
Now this is where, in hindsight, the Tablo solution for you will break down. You most likely share the Retirement Ccommunity Internet and does not have an Internet connection of your own. So your Tablo, your Roku, and optionally your TV will all connect to the shared Internet. That already presents problems since Tablo does not perform optimally if it is not connected via Ethernet to the router.
There are solutions to this, but I honestly don't think it will fly and in the end it may cost a bundle.
I'm going to reiterate that you are probably better off if you need over-the-air DVR capability, to get a Tivo Roamio or the other solution (Channelmaster?) that were mentioned in this thread.
About that think I promised to talk about later. If your cable provider does not want you to connect a DVR to the shared cable/Internet, they may also balk about you connecting a Tablo and/or Roku. Also, both of those significantly loads the Internet connection, which may be detrimental to those you share with.