Fortnite pc: how do I set it immediately, for example, build a wall when I press the button?

I switched to pc today. So I have, for example, the ground on "Q". If I press q but I still have to press the left mouse button so he builds the ground. Can one adjust it so that he builds that if I press q and not first with the mouse button must confirm?

The one with the left mouse button is normal, you probably have to rehearse pro or how it means to play 2 times e.g. R1 had to press this is like the normal build q is only to select

Thank you.