Dip your toes in

Photo of someone getting their toes wet
The phrase dip your toes in means to try something in a small, careful way before doing it fully. It often describes starting gently because you are unsure.
The idiom comes from the literal action of dipping your toes into a body of water to check the temperature before you get into it to go swimming.

She dipped her toes in coding by making a small game.