How to use friend system

I noticed that some of the old commands like /f l work but it does not show me which friends are online.
I also cannot find a way to view my friends game name for joining on them or how to join their game from the battle.net system.
how do i use the new friend commands to see which friends are online, the name of the game they are in, and to join on top of friends who have friends list joining enabled?

Yes, you can have more than 1 account merged under 1 battle.net account. You should be aware it’s against Blizzard’s ToS though, and can result in the loss of the whole account. It’s not too hard to figure out when they see 2 simultaneous logins to the same battle.net account from 2 different places.

Thanks
Daniel Charles