Can someone breifly show me what a InputBegan event looks like?

Thanks in advanced for help

UserInputService only works in LocalScripts. The wiki has some examples, too. Check out the wiki for InputObject to see all available types of input (you can also check for things like mouse clicks/scrolls).

local p = game.Players.LocalPlayer
game:service("UserInputService").InputBegan:connect(function(inputObject,gameProcessed)
	if gp == false and inputObject.KeyCode == Enum.KeyCode.F then -- if the key is F and the player isn't typing
		print(p.Name.." pressed F!")
	end
end)

From seeing an earlier question of yours, I'll make some code for you in context:

This is a LocalScript.

local gui = script:WaitForChild("TabGui") -- the gui
local uis = game:service("UserInputService")
local p = game.Players.LocalPlayer
local curGui -- for later

function guiToggle(enabled) -- function for toggling gui
	if enabled == true and not curGui then -- if the gui is closed and the script requests for it to be open
		curGui = gui:Clone() -- clones gui
		curGui.Parent = p.PlayerGui -- parents it
	elseif enabled == false and curGui then -- if the gui is open and the script requests for it to be closed
		curGui:Destroy() -- destroys gui
	end
end

uis.InputBegan:connect(function(key,gp)
	if gp == false and key.KeyCode == Enum.KeyCode.Tab then -- if the gui toggle is eligible to run
		if not curGui then -- if the gui is closed
			guiToggle(true) -- invokes the function, requesting to be opened
		else
			guiToggle(false) -- invokes the function, requesting to be closed
		end
	end
end)

Hope I helped!

~TDP