Tools have 4 different events that players can fire.
Activated -- Fires when the player clicks or holds Mouse1
Deactivated -- Fires when the Player releases Mouse1
Equipped -- Fires when the player Equips the tool (works without handle aswell.)
Unequipped -- Fires when the tool is dropped or sent to the backpack
Below is an example of the Activated Event.
print(script.Parent.Parent.Name) --This will be the User's name if the script is a direct child of the tool.