"a roblox script that spawns a part in front of you unanchored when you press Q, and tell where to put it"

-- LocalScript inside StarterPlayerScripts 
local player = game.Players.LocalPlayer
local character = player.Character or player.CharacterAdded:Wait()
local userInputService = game:GetService("UserInputService")

local function spawnPart()
    local part = Instance.new("Part")
    part.Size = Vector3.new(5, 5, 5)
    part.Position = character.HumanoidRootPart.Position + character.HumanoidRootPart.CFrame.LookVector * 10
    part.BrickColor = BrickColor.new("Bright red")
    part.Anchored = false
    part.Parent = workspace
end

local function onInput(input, gameProcessed)
    if input.KeyCode == Enum.KeyCode.Q and not gameProcessed then
        spawnPart()
    end
end

userInputService.InputBegan:Connect(onInput)

-- Instructions 
-- 1. Open Roblox Studio
-- 2. Create a new place or open an existing one
-- 3. In the Explorer window, navigate to StarterPlayer > StarterPlayerScripts
-- 4. Right-click on StarterPlayerScripts and click on "Insert Object" then select "LocalScript"
-- 5. Copy and paste the code above into the LocalScript
-- 6. Test the game in Roblox Studio by clicking "Play"