Not a dumb question you don't necessarily need two HDMI outputs from your GPU or on-board graphics, you just need two monitors capable of the same resolution you want, and cables capable of pushing that resolution from the PC to the monitors, AND ports for both of those cables on your PC or GPU. If you're looking to mirror a 1080p resolution output to two monitors, makes sure both monitors can do 1080p, then get HDMI, display port, and/or DVI cables for those monitors, connect the both either to your on-board PC display outputs or your GPU outputs, power on your PC, then go into display settings and set them to mirror your display to both monitors. You should be good then