I don't understand the two SimpleStorages at line 4

[SonRianoh]

function sfStore(uint256 _simpleStorageIndex, uint256 _simpleStorageNumber) public {
    // Address
    // ABI - Application Binary Interface
    SimpleStorage simpleStorage = simpleStorageArray[_simpleStorageIndex];

[krakxn]

Just from that code snippet: I can comprehend this - simpleStorage (a type of SimpleStorage) is being assigned the value at simpleStorageArray[_simpleStorageIndex].

Simply, simpleStorage holds whatever is inside simpleStorageArray (at index _simpleStorageIndex)

Hope this helped!

[SonRianoh]

Thanks!