Jlobes,
Answering your original question on what to do to get started:
First, go to Neptune Systems' website, find the 'comprehensive reference manual', download it and start reading it.
https://www.neptunesystems.com/support/docs/
Second, go the the Neptune Systems Community forum, join it and search for discussions about others who have picked up used Apex systems or are reinstalling Apex systems on a new tank.
https://forum.neptunesystems.com/
Third, Don't be afraid to 'fool around' with your newly acquired Apex components to get used to it. You can do this without anything having to be put into your aquarium.
Tips:
1. Never plug a USB device into an Apex module or device even though the Aquabus cable is a type of USB cable. The Aquabus runs at a different voltage than USB interfaces. If you plug any USB device into the Apex components you will fry something, probably not your fish.
2. If your aquarium equipment is spread out over long distances you can get longer Aquabus cables, but the total of all of your Aquabus cables must not exceed 200 feet.
3. Neptune Systems tech support is excellent. I presume you will qualify for their service, but I don't know for sure.
4. There are very knowledgeable users on the Neptune Systems' forum, very helpful and very polite. It is the best forum I have ever participated in.
5. Set everything up separately from your aquarium and get started getting the hang of how things work.
6. Don't expose PH or ORP probes yet, leave them alone, unattached to the system until you are ready to use them in a tank.
7. Perform the module updates for all of your Apex modules.
8. Learn to use the local dashboard interface and the Fusion web based interface.
The local dashboard is accessed on your LAN at the URL: "//ip address of your apex" - probably something like: "//192.168.1.101" but use the IP address that was actually assigned by your system.
The Fusion interface is at the internet URL:
https://apexfusion.com/apex
9. Figure out where and how you will mount everything. It does not all have to be co-located. The Aquabus will
'daisy chain' modules and devices together. There are forum posts on this subject with good photos to give you ideas.
10. Don't be afraid to erase everything and start all over after you have learned how to program the Apex. You will do better to start fresh after you know what you are doing.
11. Go to the Reeftronics web site and join up. Make a contribution if you can. Reeftronics will help you with documenting and understanding your programming and will make it easier for others to help you when you need it.
Good luck, fab