Stop! Don't learn to airbrush on a model you intend on finishing. Instead use a test mule, a piece of crap you screwed up in the past. Learn before applying to a good model.
You can brush paint, nothing stopping you there, but Tamiya paints prefer IMO to be airbrushed. If you elect to brush using them, be sure to have the right brushes for the task. Not all paint brushes are the same.
Not familiar with the Aztec airbrushes from Testors, sorry.
Words of modeling wisdom...Focus on the build skills, paint doesn't cover the flaws, it accentuates them.