How do i make a server sided key detection or a client side one that can send info to the server ?

What you're trying to accomplish can be completed through the use of Remote Events. These events allow the client to communicate to the server and vice versa. From the client you can call :FireServer() and pass in arguments. You can then have a server script listening for when that event is fired through .OnServerEvent <- (player, ...). Within that server script you can make changes to the workspace that will be visible on all clients as they were made through the server. If you look at the resource I linked above you can find out more about Remote Events and how to properly use them.