When one Google this the Kurulus -Osmar series, that follows Resurrection Ergutrul, it says Roku is the only channel or streaming media that has it but I can’t find it! What am I missing?
I don't think you are missing anything. Kurulus-Osman does not seem to be available yet for streaming. I did see that Resurrection Ergutrul is available through Netflix, but not Kurulus-Osman.
You can watch on Youtube from what I am assuming is their official channel. (https://www.youtube.com/c/Kurulu%C5%9FOsmanatv)
It does seem to be in Turkish.
If watching on your Roku, just launch Youtube Channel/app and search for Kurulus Osman and locate this channel.