How do you put the recently online such as, users online in the past 15 minutes at the bottom of my forums? I've seen most forums has it. Also the recent topic discussed panel or bar on the left side. Is this some kind of plugins or setting or what?

if you are an admin- you have a button in the left side of the community and if you press it you can add new block including the one you asked for.

I've found it. Thank you very much.