I wrote a series of Apex tutorials here on Reef2Reef:
https://www.reef2reef.com/ams/authors/suncrestreef.93940/
However, before reading my tutorials, I highly recommend following Neptune's Getting Started Guides for the initial setup of the Apex and each of the modules:
https://www.neptunesystems.com/getstarted/
Another great resource is Derrick Picker's Reef Automation channel on YouTube:
And then there's Neptune's Community Forums which contains over 10 years of Apex questions and answers:
https://forum.neptunesystems.com/forum.php
Good luck!!!