Practice.....
Thats the most important thing about your new tool. As for what to spray to practice?? The "experts" told me to use Ink...it worked perfectly to learn what my airbrush could do...lines, dots, circles...etc.
What it did NOT teach me was how to spray plastic car bodies. So my advice is get a couple of kits cheap...parts missing or damaged
will work. then get some of the paints you want to use.Tell us what you got and we will tell you what you need to do...prime, color, clear, thinner? cleanup? After you get the rough idea then you start the real practice...and 20 years from now you will still be practicing...constantly learning new ideas and techniques
PS ditch the latex unless you're painting a dollhouse