HELP!!! Chi-Square Tests

What is the difference between Homogeneity of proportions across two or more groups, Test of independence, and Goodness of fit test?

Also, how would you know which test was used if all you are given is X-squared=31.3695, df=2, p-value=1.542e-07?

And based on those outputs, how do you decide what your decision is?

I'm feeling really lost in my class right now and would appreciate ANY practical explanations or help anyone can offer.