**You must change your password from the temporary one before accessing any Google website**
Go to classroom.google.com — or just Google "Google Classroom" and click the first result. Sign in with your college email address and password. If you have a personal Google account already, then you need to be confident switching between the two: https://www.youtube.com/watch?v=ubu1xzajR4Y
You can also download an app to your phone in the App Store/Google Play store - very useful
Your tutor will give you a class code to enter (click the + button, top right, then "Join class")
Inside each class, there are three tabs:
Stream — announcements and updates from your tutor, newest at the top.
Classwork — all your assignments, quizzes and any materials. This is where you'll spend most of your time.
People — your classmates and tutor contact details.
This will vary per course - please speak to your tutor. For general help see here: https://www.youtube.com/watch?v=JxoSbp5F9m8