How do i make it so my hand deals damage only when i press F button?

SCRIPT :

local replicatedStorage = game:GetService('ReplicatedStorage')
local PunchingRemote = replicatedStorage:WaitForChild('Punch')
local anim1 = Instance.new('Animation')
local anim2 = Instance.new('Animation')
anim1.AnimationId = 'http://www.roblox.com/asset/?id=6985138442'
anim2.AnimationId = 'http://www.roblox.com/asset/?id=6984519609'
local var = 1
local debounce = false
local canDoDmg = true
PunchingRemote.OnServerEvent:connect(function(plr)
	local track1 = plr.Character.Humanoid:LoadAnimation(anim1)
	local track2 = plr.Character.Humanoid:LoadAnimation(anim2)
	local character = plr.Character
	local humanoid = character:WaitForChild('Humanoid')
	if var == 1 and debounce == false then
		debounce = true
		plr.leaderstats.Effort.Value = plr.leaderstats.Effort.Value + plr.Stats.Earnings.Value
		track1:Play()
		var = var + 1
		wait(1)
		debounce = false
	elseif var == 2 and debounce == false then 
		debounce = true
		plr.leaderstats.Effort.Value = plr.leaderstats.Effort.Value + plr.Stats.Earnings.Value
		track2:Play()
		var = 1
		wait(1)
		debounce = false
	end
	
	plr.Character.RightHand.Touched:connect(function(hit)
		if hit.Parent.Humanoid and canDoDmg then 
			hit.Parent.Humanoid:TakeDamage(plr.Stats.Damage.Value)
			canDoDmg = false
			wait(1)
			canDoDmg = true
		end
	end)
	
	plr.Character.LeftHand.Touched:connect(function(hit)
		if hit.Parent.Humanoid and canDoDmg then 
			hit.Parent.Humanoid:TakeDamage(plr.Stats.Damage.Value)
			canDoDmg = false
			wait(1)
			canDoDmg = true
		end
	end)
	
	
end)

while wait(4) do
	if var == 2 then
		var = 1
	end
end

LocalScript :

local UIS = game:GetService('UserInputService')
local replicatedStorage = game:GetService('ReplicatedStorage')
local remotePunch = replicatedStorage:WaitForChild('Punch')
UIS.InputBegan:connect(function(input, isTyping)
	if isTyping then return end
	if input.KeyCode == Enum.KeyCode.F then
		remotePunch:FireServer()
		end
end)

Basically, when i go next to a play and my hand touches his body it deals damage anyway, and i want it to deal damage only when i press a certain key. Please teach me, i don t want a script i want an explanation so i can understand it and learn it for further projects !

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