How to add the boundary condition

Hi all,

I have a storage tank, in which i have to simulate the water storage and it's effect on the tank. as i have to apply the water as a boundary condition in the vessel which has a density of 1000kg/m3. i am little bit confused how to apply the water in the storage tank.

please help how to do it?

Regards

devi samal

SolidworksSimulation