Searching for Essentrics TV.
Will not allow me to add the channel.
any help/advice?
I'm in the US. If you can't see that link, you might not be in the US (or at least Roku may think you are not) since some channels are only available in certain areas.
In addition to what @Strega wrote, it may also depend on what Roku model you have, so if you are in the US and you have a fairly old Roku device it may not be available.