How do I let players be able to bind a certain skill to a certain key?

I'm currently working on an RPG with some skills and I want to make it so that players can bind skills to their preferred keys, however, I can't think of a way to make that happen. Here's what I have tried:

local enabled = true
local player = script.Parent.Parent
local character = player.Character
local uis = game:GetService("UserInputService")
local pkey = script.PressedKey.Value
local jutsulife = script.JutsuLife.Value
local cooldown = script.Cooldown.Value

uis.InputBegan:connect(function(input, gpe)
    if not gpe then
        if input.UserInputType == Enum.UserInputType.Keyboard then
            if input.KeyCode == pkey then
                if enabled then
                    enabled = false
                    local animTrack = character.Humanoid:LoadAnimation(script.HandSigns)
                    animTrack:Play()
                    local signsound = Instance.new("Sound", character.Head)
                    signsound.PlayOnDestroy = true
                    signsound.SoundId = "http://www.roblox.com/asset/?id=245030009"
                    signsound.Volume = 1
                    signsound.Pitch = 1.5
                    signsound:Destroy()
                    wait(1)
                    local jutsusound = Instance.new("Sound", character.Head)
                    jutsusound.PlayOnDestroy = true
                    jutsusound.SoundId = "http://www.roblox.com/asset/?id=147722098"
                    jutsusound.Volume = 1
                    jutsusound:Destroy()
                    wait(0.5)
                    animTrack:Stop()
                    local firesound = Instance.new("Sound", character.Head)
                    firesound.PlayOnDestroy = true
                    firesound.SoundId = "http://www.roblox.com/asset/?id=245029978"
                    firesound.Volume = 1
                    firesound:Destroy()
                    game:GetService("Chat"):Chat(character.Head, "Katon: Gokakyu no Jutsu!", "Red")
                    local x = Instance.new("Part")
                    x.BrickColor = BrickColor.new("Really red")
                    x.Size = Vector3.new(10, 10, 10)
                    x.TopSurface = "Smooth"
                    x.BottomSurface = "Smooth"
                    x.Shape = "Ball"
                    x.Name = player.Name
                    x.CanCollide = false
                    x.Transparency = 0.75
                    local flame = Instance.new("ParticleEmitter", x)
                    flame.EmissionDirection = "Back"
                    flame.Speed = NumberRange.new(2.5)
                    flame.Size = NumberSequence.new(2)
                    flame.Rate = 1000
                    flame.Lifetime = NumberRange.new(1)
                    flame.LightEmission = 0.5
                    flame.Texture = "http://www.roblox.com/asset/?id=288049555"
                    flame.Color = ColorSequence.new(Color3.new(1, 0.6, 0), Color3.new(1, 0.7, 0))
                    flame.LockedToPart = false
                    flame.Name = "Flames"
                    local damage = script.damage:clone()
                    damage.Parent = x
                    local y = Instance.new("BodyVelocity")
                    y.maxForce = Vector3.new(math.huge, math.huge, math.huge)
                    y.velocity = character.Torso.CFrame.lookVector*45
                    x.Parent = workspace
                    y.Parent = x
                    x.CFrame = character.Head.CFrame*CFrame.new(0, 0, -1)
                    damage.Disabled = false
                    game.Debris:AddItem(x, jutsulife)
                    wait(cooldown)
                    enabled = true
                end
            end
        end
    end
end)

The script.PressedKey is a StringValue with the value "Enum.KeyCode.R", but when I press the 'R' button it doesn't work.