In order for you to build a web site using Google sites, you need to have a Google account. If your email is in the format YourName@gmail.com, you have a Google account, and many people with emails from aol.com or yahoo.com or verizon.net, etc also have Google accounts. With a google account, you can create a Google site and store things in the cloud on a Google drive. Here's how to tell if you have a Google account:
Type www.google.com into the address bar of your web browser. If you already have a Google account and you're signed in, you'll see a page like this, where a circle in the top right corner has your picture or maybe your initial:
If you have a Google account, you're all set and can skip to the next step.
If you don't have a Google account, or you have one but you're not signed in, you'll see a page like this, with a sign in button in the upper right:
Click the sign in button. If you have a Google account but are signed out, just select the account (usually your email address) and enter your password to sign in. If you don't have a Google account, you can create one for free by following these instructions:
Congratulations! Now go to the next step.