Attach your monitor to the new 210 card.
When you power on, the motherboard, if it is smart enough, should recognize that is now the primary adapter.
The image will be in very low resolution, like 640 x 320 until you can download and install the nvidia graphics drivers.
If you need to make any bios changes, check the motherboard manual which should tell you how to enter the bios.
Usually, pressing del and/or F2 repeatedly during the boot process will get you there.