How to make water in Unity3D?

Question

Unity

the problem is this, I'm making a 3D game and I need to make water physics, well, in order for the character to swim, at the moment I use the OnTriggerEnter and OnTriggerExit methods in the middle of the OnTriggerEnter method is if (other.tag == "Water")
{
isSwimming = true;
rb.useGravity = false;
}
and in OnTriggerExit is if (other.tag == "Water")
{
isSwimming = false;
rb.useGravity = true;
}
then I check in Update(): if (Input.GetKey (KeyCode.Space) && isSwimming)
{
transform.Translate (0, SwimmingForse * Time.deltaTime 0)
}
and the following bugs appear that need to be fixed, when I surfaced, it moves me back into the water waist-deep, while the speed is maintained and I am pulled to the bottom
. -some oblique surface I'm flying to the side. I realized that using gravity off is a bad idea, tell me how best to do it