My first script

local Players = game:GetService("Players")
local UserInputService = game:GetService("UserInputService")

local player = Players.LocalPlayer
local character = player.Character or player.CharacterAdded:Wait()
local humanoidRootPart = character:WaitForChild("HumanoidRootPart")

local bodyVelocity = Instance.new("BodyVelocity")
bodyVelocity.MaxForce = Vector3.new(math.huge, math.huge, math.huge)
bodyVelocity.Parent = humanoidRootPart

local speed = 30

UserInputService.InputBegan:Connect(function(input)
    if input.KeyCode == Enum.KeyCode.Space then
        bodyVelocity.Velocity = Vector3.new(0, speed, 0)
    end
end)