Question: how to setup dual monitor on raspberry pi?
Answer: Step 1: Add your SD card to the Raspberry Pi. Flip over your Raspberry Pi 4 Model B and insert the SD card into the card slot, with the pins of the card facing the Pi.
Step 2: Connect your left monitor. ... 
Step 3: Connect your right monitor. ... 
Step 4: Connect your mouse and keyboard. ... 
Step 5: Power your Raspberry Pi!