How to mention someone on instagram?

[Fiona]

I recently made an instagram and I don't know how to mention someone in a comment. I read online you have to hold their username for 2 seconds and then a menu will pop up. I tried that and no menu popped up. Please help!
I have an android, by the way.

Thanks a lot!!!!!
if i put @(username) will it still come out as a hyperlink ( in blue)???

[Liana]

@(their username)

Edit: yes it will

[breathless]

@username

if you don't follow them or if they don't follow you I think it doesn't