Ok so the player clicks a gui button.
The gui button triggers a local script.
The local script triggers a remote event.
The remote event triggers a regular script.
The regular script does whatever and whatnot, but in this regular script how do I get the username of the player who clicked the gui in the first place?

2 comments
The first parameter of OnServerEvent is the player who fired it, always.
This isn't a request site. Show us the code.