Dear Xiao Bai Tu, I am very confusing now. Would you like help

Hello, My parents are in China. I took a oath in this June. I will apply green card for them. I checked some discussions and found there are a lot of forms need to be filled. But In www.uscis.gov and I-130, they don't say anything about these forms. So I am very confusing now. I don't know where to find reliable information to show me how to apply for them and which forms should I use. I wonder would you like to help me. Thanks a lot.