Gmail our email service provided by Google.
One any computer with internet, open a browser. (i.e. Google Chrome, Internet Explorer, Firefox, etc)
In the address bar, type www.gmail.com and then press enter.
Type in your email address. (xxxx@lexrich5.org with X being your username)
Then click Next.
Now sign in to ClassLink. (This is just your username, what is before the @ symbol, and password.)
Then choose the option to authenticate.
Now you should be in your email.