Give someone a big hand [Idiom] | Meaning with Examples
It's an idiomatic expression that means - to clap or applaud a performer, often as a show of approval or appreciation. (To applaud someone extensively by clapping hands.)
If you ask the audience to give a big hand to a performer, actually you are asking them (the audience) to clap the performer.
You can also ask for a big hand for someone or say that someone gets a big hand.
Examples
a) Let's have a big hand for our first act, ladies and gentlemen.
b) Mr Wells got a big hand from most of the people present.
More Examples:
a) Let's give all the performers a big hand for their hard work/amazing performance.
b) Let's give him/our special guest a big hand.