Press the Create button, it is a plus sign in the middle of the tab bar. Alternatively, you can go to the person's profile then press on Ask a question directly or if you want to ask yourself. Got to your profile and press on Ask myself.
Tap on Ask someone.
Select one of the ways you want to ask (see above: Fun ways to ask),
By default, your Ask is anonymous as indicated below with You're anonymous, tap it to ask openly i.e NOT anonymous.
If a user to ask is already selected, you can press on Send if not press the send icon button on the top right