"create a script that makes a model fly around next to you like a pet and give instructions on how to set it up"

-- local script inside the pet model 
local Players = game:GetService("Players")
local TweenService = game:GetService("TweenService")
local pet = script.Parent
local player = Players.LocalPlayer
local character = player.Character or player.CharacterAdded:Wait()
local humanoidRootPart = character:WaitForChild("HumanoidRootPart")

local function followPlayer()
    local distance = (humanoidRootPart.Position - pet.PrimaryPart.Position).Magnitude
    if distance > 5 then
        local newPosition = humanoidRootPart.Position + Vector3.new(3, 1, 3)
        local tweenInfo = TweenInfo.new(1, Enum.EasingStyle.Linear, Enum.EasingDirection.InOut)
        local tween = TweenService:Create(pet.PrimaryPart, tweenInfo, {Position = newPosition})
        tween:Play()
    end
end

while true do
    followPlayer()
    wait(1)
end

Instructions:
1. In Roblox Studio, create a new model or import a pet model that you want to use.
2. Make sure the model has a PrimaryPart set. If not, set a part in the model as the PrimaryPart.
3. Insert a LocalScript inside the pet model.
4. Copy and paste the above script into the LocalScript.
5. Place the pet model in the StarterPack or StarterGui so that it spawns with the player when they join the game.
6. Test the game and the pet should follow the player around.