Craft 3 via composer with Mamp Pro
nystudio107 just released a nice guide yesterday for setting up a Craft 3 site via composer.  No mention of Mamp Pro, but I don't think that should really be a problem if you're already used to using it, as you would just make sure your hosts file is pointing to the /web/index.php file.  The article does a great job of explaining what a lot of the terminal commands actually refer to instead of just telling you what to type in.

https://nystudio107.com/blog/setting-up-a-craft-cms-3-project