Sometimes when I’m praying, my children misbehave and do things they shouldn’t do. Is it allowed for me to snap my fingers or clap to get their attention, or use my hands to indicate to them to stop what they are doing? May Allah reward you with goodness.
Yes, you can clap with your hands to signal to them to stop if necessary.
But in case there is no danger in what they are doing, my advice to you is to try to ignore them and focus on your prayers, as sometimes this is one of Shaytan’s tricks to get our minds and attention away from our prayers.