It does get confusing. One way to help is to set the wallpaper for the TV to be different from the wallpaper on the Streambar. Is one of the HDMI inputs on the TV labeled "ARC"? If so, that's where you should connect the Streambar and then you won't need the optical cable at all. If not, then it's fine the way it is.
Assuming you do most of your viewing via Roku channels/apps, whichever HDMI input you have the Streambar connected to, set the TV to "Power on" to that input. I believe the setting is located under Settings->System->Power. Use the TV's remote to get there. Once you have everything set up, you should be able to use the Streambar's remote for pretty much everything except changing the TV's input (to something like a cable box) or watching broadcast channels using an antenna (if you do that).
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