First you go and type their names with a @ at the beginning (make sure you are following them, because it's harder to tag unfollowed person)

(@example )

And then (on the mobile device) as you are typing their name out you should a some names that are people you are following.

For example... say I wanted to tag JasTheDiamond.

I would type her name and then click on her  name.

And the name should look what it does down below. (Won't be notified if it's not)

There you go!

Howl it with me now!

Aaaaaaaaaaaarrrrrrrrrrrooooooooooooo!

Bye, lovelies Wolfies! Stay gorgeous!