How do I make It so when a player touches a brick it makes another brick spawn in?

i assume you already know about how events, the .Touched event, and debounces (aka cooldowns) work

if you don't, you should read these articles first (in this order)

https://developer.roblox.com/en-us/articles/events

https://developer.roblox.com/en-us/articles/detecting-collisions

https://developer.roblox.com/en-us/articles/Health-Pickups

-- in a script inside the part...

local canSpawnBrick = true
local cooldown = 5
local spawnPosition = Vector3.new(0, 10, 0) -- you can set this whereever

local function onTouched(hit)
    local humanoid = hit.Parent:FindFirstChildWhichIsA("Humanoid")
    if humanoid and canSpawnBrick == true then -- we don't actually need the humanoid, we just want to know if a character touched it
        local newBrick = Instance.new("Part") -- make the new brick
        newBrick.Position = spawnPosition
        newBrick.Parent = workspace
        canSpawnBrick = false -- activate the cooldown
        wait(cooldown)
        canSpawnBrick = true
    end
end

script.Parent.Touched:Connect(onTouched)