Cryptic - nothing to it! load up that little color cup, push the trigger all the way down and slowly pull back until the right amount of paint is coming out! Practice like that till you get a feel for it... then you can play around with pressures/needle pull to try to get thin lines for detail... all the rest pretty much comes with experience... and practice!!
Good luck! you got a good airbrush, it's rather forgiving to a beginner! (I had only used an AB a little when I got my 155 and it was like a magic wand for me!
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If you can try to get an extra color cup... it's nice for cleanup... pull the one with paint in it off, wipe it out (or pour it back in the bottle if there is enough), put some cleaner in it. Take the clean one and put it on the brush add cleaner and clean the airbrush.. then you can wipe out the other one, I use a qtip and rub around all the sides then a paper towel rolled into a point stuck down into the cup and twisted until the paint is out does the trick!... seems to make cleanup a bit faster!