How to Hide others your online status?
(https://i.imgur.com/fcLGrve.png)
1. Click on your profile. http://prntscr.com/jp1tlx
2. Click on Account Settings. http://prntscr.com/jp1uoy
3. Untick the option saying "Show others my online status". http://prntscr.com/jp1vcj
4. Type your password in the rectangle, then press "Change Profile". http://prntscr.com/jp1wvd
(https://i.imgur.com/fcLGrve.png)
Done
If you follow my steps correctly,when you roll your mouse down to see the users online,you should be in (Hidden) category,like this. http://prntscr.com/jp1xpu