What do you mean by "install zf2 on mac"?
You may want to follow the Getting Started: http://zf2.readthedocs.org/en/latest/user-guide/overview.html
Using the skeletton app, you will be able to get a fully working ZF2 project (Composer will download all needed files).
If you want to get a MAMP Server with ZF2 included, you may want to use Zend Server CE which is free and is working well. Akrabat (Rob Allen) wrote a post on his blog about how to setup Zend Server CE on MacOS.