What exactly do the Maven build... choice inside the Eclipse Run As?

I am absolutely new in Maven and I am studying it. I am using Eclipse

I have the following doubt: into Eclipse I have a Maven project.

If I select this project and I do right click on it and then I select the Run As option I have some choice. What exactly represent these choice? Are Maven tasks or what?

In particular to perform my project I have 2 possible choices:

1. Maven build
2. Maven build...

What exactly does these tasks? It seems to me that build the project and perform the related unit test. Is it true or am I missing something?

What is the difference between the previous choices. In the tutorial that I am following it is used the Maven build... and then set the clean package as goals. What exactly do this goal?

Tnx