Post work for student on google classroom

Hi,
I didnt post any work on google classroom before, even didn't post any woek or activity on the google classroom. In the new job the rest of teachers use it. They gave me gmail account. I login on google classroom and there was no my class so I create the class. Now what do I do next. May I give the code to all student or If I upload the work in each calss they will recieve automatically. Please explain me step by step. I have created a class in google classroom and got a code. Next step plz