DiamondStorage.sol

// SPDX-License-Identifier: GPL-3.0
pragma solidity ^0.8.0;

contract FacetA {

    struct DiamondStorage {
        uint firstVar;
        uint secondVar;
    }

    function getStorage() internal pure returns(DiamondStorage storage ds) {  
        // Specifies a random position in contract storage
        // This can be done with a keccak256 hash of a unique string as is
        // done here or other schemes can be used
        bytes32 storagePosition = keccak256("diamond.storage.facetA");
        // Set the position of our struct in contract storage
        assembly {ds.slot := storagePosition}
    }

    function getVars() public view returns(uint, uint) {
        DiamondStorage storage s = getStorage();
        return (s.firstVar, s.secondVar);
    }
  
}

contract FacetB {

    struct DiamondStorage {
        string thirdVar;
        string fourthVar;
    }

    function getStorage() internal pure returns(DiamondStorage storage ds) {  
        bytes32 storagePosition = keccak256("diamond.storage.facetB");
        assembly {ds.slot := storagePosition}
    }

    function setVars() public  {
        DiamondStorage storage s = getStorage();
        s.thirdVar = "Ashwin";
        s.fourthVar = "Yardi";
    }

    function getVars() public view returns(string memory, string memory) {
        DiamondStorage storage s = getStorage();
        return (s.thirdVar, s.fourthVar);
    }
  
}