my water is not solid anymore but its like a walk through wall , how can i make it be like water and swimmable
A common method in first person games is to disable the gravity for your player's rigidbody when below the water surface.
You'll then want to apply a slight constant upwards force on the player so it seems as though they are dragged upwards when not actively swimming down.
Finally, you'll want to modify your movement script (you haven't said how you're moving the player yet), so that you can move in all directions rather than just fwd/back left/right on the surface.
If you're using the FPS controller for this, you will probably need to modify the scripts so that - when undwater - the forwards motion is applied in the absolute direction of the camera, rather than just the direction of the rigidbody (which always remains upright).
Have you tried checking the Island Demo? There is some "wet" water there. You can copy how it's done. It's using just Mesh and scripts for Wave.
After that, for swimming you'll need to modify the FPSWalker script. You can use the underwatereffects as example. But it will greatly depend on what you want to do.
At any pace, you'll have to know how to script to achieve your desired results.