Making A Chess Multiplayer Game

I am trying to make a Chess multiplayer game in Visual Basic. Its a two player which will be played in a normal way and not even over LAN. So far, I am done designing the board.

My logic is: First, on clicking any square, the click event handler will check whether a piece resides on that square. If not, then it checks if a piece is to be moved to that square. If both are negative, then it does nothing.

Now, the problem with this is, how do I code the click events? Also, I have represented the board using a 2dimensional array. But how do I update the positions after every move? And how do I check whether legal move is being executed? One more thing I want to add is whenever a piece is clicked, the possible legal squares should be highlighted.

For this, what I did was, for every click event on any square it checked if there was a piece. If there was a piece, then it highlighted all possible moves for that piece using If-Else-If logic, but it turned out to be too cumbersome and too long. And another problem which arose was, how do I know that if the user clicks an empty square to move the piece there?