Not sure about on the tab but here's how you do it on the s5. Maybe its the same. (HTH!)
Slide down the menu from the home screen and select the settings button (the cog looking thing in the top right corner)
Scroll to devices and select "display"
Select "Screen rotation"
Slide the green slider in the upper right corner from right to left.
Done!
Another method to quickly adjust is to just use quick tiles.
If you swipe down the notification panel using two fingers instead of one you get the full set of quick settings tiles. One of them is called "Screen Rotation" which is the icon visible as the 2nd from the right in the 1st screenshot drchimrichalds posted. This will toggle rotation lock, so set rotation how you want it and then disable rotation.
It allows me to set specific rotations for specific applications. Very handy since some of my applications I prefer to force into a particular rotation.