How do I make a tool go onto a certain brick on click?

So like, if I clicked a certain brick, the tool would go onto it, and then if I clicked it again, I would pick it back up again.

You could do this with ClickDetectors.

For example, you could have a ClickDetector in the brick. There would be a script in that brick that would put the tool onto the brick, and a ClickDetector in the tool, and weld the tool to the brick, then detect when the tool is clicked and give it back to a player... Here, let me use an example:

local hasTool = false

local function setupTool(tool)
	hasTool = true
	tool.Parent = script.Parent

	local clickDetector = script.Parent.ClickDetector:Clone()
	clickDetector.Parent = tool

	local handle = tool:FindFirstChild('Handle')

	local toolWeld = Instance.new('Weld', tool.Handle)
	toolWeld.Part0 = handle
	toolWeld.Part1 = script.Parent
	toolWeld.C0 = CFrame.new(0, -1, 0)

	clickDetector.MouseClick:Connect(function(plr)
		local character = plr.Character or plr.CharacterAdded:Wait()
		local humanoid = character and character:FindFirstChildWhichIsA('Humanoid')
		local backpack = plr:FindFirstChild('Backpack')

		if not humanoid or not backpack then return end

		toolWeld:Destroy()
		clickDetector:Destroy()

		hasTool = false

		tool.Parent = backpack
		humanoid:EquipTool(tool)
	end)
end

script.Parent.ClickDetector.MouseClick:Connect(function(plr)
	if hasTool then return end

	local character = plr.Character

	if not character then return end

	local humanoid = character:FindFirstChildWhichIsA('Humanoid')
	local tool = character:FindFirstChildWhichIsA('Tool')
	local handle = tool and tool:FindFirstChild('Handle')

	if not humanoid or not handle then return end

	humanoid:UnequipTools()

	setupTool(tool)
end)

This is untested, I'd substitute the CFrame for C0 with something else, and it'll get messed up if you touch the tool to automatically pick it up again, but it could probably work.

Hope this helps!