Do you have a DB9 Serial port or a USB->Serial adapter to connect the console? You can't connect the console port to the Ethernet port on your computer to access it. A serial connection is required.
Regarding upgrade, once you're logged in you've got several options. You can look into documentation for creating a stack and then upgrading them, or you can do every switch individually.
Please consider taking a look at
GTAC Knowledge to search for articles on how to configure stacking and upgrade the switches. A search for "upgrade exos" returns several useful articles for this.
You may decide to go ahead and
open a support ticket so someone can help guide you through the basics. Your SE or reseller should also be able to assist.