Welcome to the forum, and welcome back to the hobby! Things have changed a lot over the years. I'm 53 and build for a few years and then get out for a few years. Every time I come back I find tons of new things going on.
Some people bend coathangers to hold their models, some stick a dowel or pencil in an exhaust or prop hole. I just use a block of styrofoam. I paint with acrylics, and they dry so quickly that I just site the model on a styrofoam block, spray one side, let it dry for a few minutes, flip it over and spray the other side. A couple of hours later I repeat the process.
Grab the airbrush, load it up, and practice on some scrap. Practice is the key to using an airbrush. If you need any tips on using it, you can get tons of help right here!