How to check for wires in a wall

[puffinpants]

I need to install a safety gate at the top of the stairs urgently. We have an electric drill but I don't know how - or if I need to check for wires in the wall before I do it.

What's the best way to do this?

You can buy a little detector that scans the walls.

www.amazon.co.uk/dp/B01DP3Y7WK?psc=1

I have never bothered but obviously if the hole is to be directly above/ below a socket/ switch then there's likely to be a wire there so avoid