How do I set up dual monitors?

You will need to set up your screens like you would do individually. Each screen needs a power cable and a signal cable which connects to your PC. Also, make sure your PC has the required ports before purchasing. 

Unless your monitor has daisy chaining ability, which will usually mean a DisplayPort cable from monitor 1 to 2, and potentially a USB-C cable from monitor 1 to your laptop/PC.