I made a sub Guide on reddit a few months back. Some of this has changed a bit with the new azerite traits but this should be a good starting point for you.
About keybinds/stealthbar:
This is tricky to get setup correctly. If you are used to having stealth specific abilities on 1-5 on your stealth bar you will run into problems with Sub. Sub requires using all of your dps abilities while in shadow dance. So as painful as it is, it is worthwhile to bind your “stealth required” abilities somewhere other than the stealth bar.
An alternative is a shadow dance macro for all of your abilities. I used one for a while that would put number 3 as Sap during actual stealth, but would change to eviscerate during shadow dance or no stealth. This was useful for a while but eliminated the possibility of eviscerating from stealth/vanish. I had to retrain my muscle memory a bit but I currently have no stealth specific abilities on my main bar anymore.
Note: I also made a video during that time for the rotation in the guide above. You can see my old macro in action on button 3.
