How would i go about moving an object with mouse only 4 studs at a time?

player = game.Players.LocalPlayer
mouse = player:GetMouse()
model = game.Workspace.Model

tool = script.Parent
 
function onActivation()
    print("Tool activated")
model = nil
end

function active()


mouse.Move:connect(hover)	
end

function hover()
	local function onKeyPress(inputObject, gameProcessedEvent)
	if inputObject.KeyCode == Enum.KeyCode.R then
		model:SetPrimaryPartCFrame(CFrame.new(mouse.hit.p.X,1.5,mouse.hit.p.Z) * CFrame.Angles(0,90,0))
	end
end
 
game:GetService("UserInputService").InputBegan:connect(onKeyPress)
	if model ~= nil and mouse.Target.Name == "Base" then
	print(mouse.hit.p)
	model:SetPrimaryPartCFrame(
		CFrame.new(mouse.hit.p.X,1.5,mouse.hit.p.Z)) -- THIS IS WHERE MOVEMENT HAPPENS
	else
		print "No object"
	end
	
	
	
	
end
tool.Equipped:connect(active)
tool.Activated:connect(onActivation)