I have my main display plugged into my GPU (hdmi). I also want to connect another monitor through HDMI but when connecting it to the motherboard nothing happens. I tried going into the BIOS and enabling the multi display option that I saw in videos but I don't have that option in my BIOS. Is there any other way to do this?
Without an APU installed the ports on the motherboard are useless. All displays will need to be plugged into the GPU. If your displays only have HDMI and the GPU only has 1 HDMI then you'll need to use an adapter. The GPU likely has a displayport(guess since you didn't post the specific make and model) so a displayport to hdmi adapter would work.