Dip your toe in the water
Meaning: to try something slowly and carefully before you make a big commitment. If your first, small experience is successful, you might do something more in a bigger way. The expression comes from testing the temperature of water (in a bathtub, swimming pool, or pond) with your toe before you put your whole body in.
Before starting her own bakery business, she dipped her toe in the water by selling bread at a farmer’s market.