You cannot make music *inside* a Roblox game. Roblox games are for playing; creation happens in Roblox Studio (Windows 7+ compatible) using external audio tools.
Export as MP3, WAV, or OGG (Roblox supports all).
local sound = script.Parent.Sound
sound:Play()
sound.Volume = 0.5
sound.Looped = trueRoblox Developer Hub has full tutorials on audio implementation.