In this video you can see the steps of preparation as follows:
Prepare the injection equipment: First, prepare a syringe with a thin needle, and make sure the syringe and needle have been sterilized, and fill the syringe with an appropriate amount of sterile water.
Locate the injection point: Find the injection port or preset injection point on the kidney model, usually these points will have obvious markings or interfaces designed for liquid injection.
Slowly inject water: Insert the needle into the injection port, slowly and evenly inject water into the 3D model organ, make sure there are no bubbles during the injection process, and observe the water flow inside the model to confirm the injection effect.