How to get bytecodeHash from CREATE2 library?

Smart Contracts
1 
    function computeAddress(bytes32 salt, bytes32 bytecodeHash) internal view returns (address) {
        return computeAddress(salt, bytecodeHash, address(this));
    }

How do I get the bytecodeHash from a contract? I can get the bytecode, but I've never gotten the hash before. I am trying to use the CREATE2 library from OZ. I don't know where to look to be able to create a hash from a contract. I have googled and not much comes up.

bytecodeHash <--- I need to create this so I can call that function.

I am using hardhat.