How can I get this tool to only do the damage one time instead of every tick there is connection?

I'm learning how to script and saw this in a tutorial but it repeats the damage to fast. How can I make it only hit for the "TakeDamage" once?

local sword = script.Parent -- variable to set string "sword" as the laser sword tool remember "." is indexing
local canAttack = true -- create a boolean variable 
local canDamage = false

function onTouch(part)
	local character = part.Parent
	local player = game.Players:GetPlayerFromCharacter(character) -- GetPlayerFromCharacter is a built in function of Player class
	
	if player then
		if canDamage == true then-- "== is used to compare" where as "=" is used to set something
			
			character.Humanoid:TakeDamage(20)
		end
	end
end
sword.Blade.Touched:Connect(onTouch) -- ".Touched" is indexing an event that returns the part it touches

function Attack()
	
	local attack = sword.Parent.Humanoid:LoadAnimation(script.SwordSwing) -- variable that sets the players swordswing animation
		
	if canAttack == true then
		attack:Play() -- playes the "attack" animation that was set in the variable up above
		canAttack = false
	
		canDamage = true
		wait(0.5)
		
		canDamage = false
		wait(0.25)
		canAttack = true
	end
	
end
sword.Activated:Connect(Attack)

Well, you just don't set it back to true/false. So here is the solution:

local sword = script.Parent -- variable to set string "sword" as the laser sword tool remember "." is indexing
local canAttack = true -- create a boolean variable 
local canDamage = false
local debounce = true

function onTouch(part)
    local character = part.Parent
    local player = game.Players:GetPlayerFromCharacter(character) -- GetPlayerFromCharacter is a built in function of Player class

    if player then
        if canDamage == true then-- "== is used to compare" where as "=" is used to set something

            character.Humanoid:TakeDamage(20)
        end
    end
end
sword.Blade.Touched:Connect(onTouch) -- ".Touched" is indexing an event that returns the part it touches

function Attack()

    local attack = sword.Parent.Humanoid:LoadAnimation(script.SwordSwing) -- variable that sets the players swordswing animation

    if canAttack == true and debounce == true then
        attack:Play() -- playes the "attack" animation that was set in the variable up above
	debounce = false
        canAttack = false

        canDamage = true
        wait(0.5)

        canDamage = false
        wait(0.25)
        canAttack = true
    end

end
sword.Activated:Connect(Attack)

I added a debounce variable so it only works once. I hope that helps!