the older macbook pros require a mini displayport adapter, for the one with vga, you will need this: [https://www.apple.com/shop/product/MB572Z/B/mini-displayport-to-vga-adapter] and for the other one, the usb ports are for data, not video, it might not even be possible to use two screens on your model, and that other one would require a mini displayport cable, which should have been included