First time building a robot, first time working with Arduino. Need some help.

[Jmac68]

I started this project back in 2015, then put it away for over five years. I am coming back to it now. I asked JColvin some questions back then and got some helpful answers. I would like some help now. I am willing to pay a fair rate for some expertise to get me over the hump. The machine construction is 99% complete. I am now connecting the wiring and then getting ready to learn Arduino. My two starting point questions: I have eighteen Nema 17 steppers. I don't understand which I/O ports I can use to connect them to. Could someone provide me a list of which ports on the Max32 I should connect the 18 x 2 leads from the Nema 17 steppers. Question #2: I am also trying to control the flow of gas and propane with two mass flow controllers. This might be an issue. They are controlled with analog 0-5v. I have two PWM to analogue convertors. I know the Max32 outputs 3.3 volts but this might be enough. The flame I am trying to produce is very small. I am sure it would not even require a 25% valve opening in either mass flow controller so 3.3 volts may be just fine. Oh, and if I need to switch boards to something that outputs 5v that's fine as well. Whatever it takes to get this done. I also have a thermocouple, a spark arc ignition module, and a one channel relay to hook up but I'll save those for later. Right now I'm trying to get a handle on which pins I connect my eighteen Nema 17 steppers to and which pins I should use for PWM to analog out for controlling the mass flow controllers. I have literally no experience with anything I am working on here. I've never built any sort of machine, never worked with stepper motors, mass flow controllers or Arduino so I'm an absolute newbie. This is my first project of this type. Any help would be greatly appreciated. And I do have some funds available for paid expert assistance. Thank you in advance.