Use the blue @ I didn't get the ping because you didn't click on it and also you can just type the name I show you how.

How to multi-ping when you can't find the @ or type it

There is a Ping users at the top when you are writing a post and you can do this, ex: Fallenangel, Christinewhogaming

and you can at more people, but you just need to remember to put commas, after each user's name...And be careful do not forget any or it'll take it has a not existent username.
You can also open the forum thread on a new page. :)

Ps: Do you speak another language...Or are you on a mobile (aka cellphone)?