"script for an existing ui that makes it fade in and swipe up when the player gains coins, showing how many coins they gained, for 2 seconds and then fade out"

-- local script inside the UI element 
local TweenService = game:GetService("TweenService")
local Players = game:GetService("Players")
local player = Players.LocalPlayer
local coinUI = script.Parent
local coinText = coinUI.CoinText

local fadeInInfo = TweenInfo.new(0.5, Enum.EasingStyle.Linear)
local fadeOutInfo = TweenInfo.new(0.5, Enum.EasingStyle.Linear)
local swipeUpInfo = TweenInfo.new(0.5, Enum.EasingStyle.Linear)

local fadeIn = TweenService:Create(coinUI, fadeInInfo, {BackgroundTransparency = 0.5, TextTransparency = 0})
local fadeOut = TweenService:Create(coinUI, fadeOutInfo, {BackgroundTransparency = 1, TextTransparency = 1})
local swipeUp = TweenService:Create(coinUI, swipeUpInfo, {Position = coinUI.Position + UDim2.new(0, 0, -0.1, 0)})

local function onCoinsChanged(value)
    coinText.Text = "+ " .. value .. " Coins"
    fadeIn:Play()
    swipeUp:Play()
    wait(2)
    fadeOut:Play()
    wait(0.5)
    coinUI.Position = coinUI.Position + UDim2.new(0, 0, 0.1, 0)
end

player.leaderstats.Coins.Changed:Connect(onCoinsChanged)