AutoCAD for MAC is not specifically designed for "commercial ducting", you'll end up still doing it the old way of drafting by hand on a computer instead of paper.

AutoCADMEP or AutoCADMECHANICAL (both for WindowsOS) may be the more appropriate CAD tools for your type of work. Which of these two specialized AutoCAD versions do your peers in your industry use in your region? Find out.

There are many Autodesk Training Centers around the globe, probably good for you to start there then move on to online to fill in the gaps after you understand all the basics. You can find one here https://www.autodesk.com/training/authorized-training-centers

HTH