It is a bad idea to fly alone,from a safety aspect. Take someone with you who can drive you to the nearest emergency room.
Go to Alan's hobby Model and R/C FAQ web links (Google search) all kinds of info on that site for beginners.
I'm not familiar with the Boomerang 40, is it a high wing trainer with tricycle u/c? What kind of surface do you have to fly off, grass or pavement? If it is grass I would suggest a set of larger diameter wheels.
Before going to the flying site check the tracking of the U/C to see if it runs straight. Try it on your driveway, with the engine OFF.
When you arrive at the flying site, first thing to do is a range check on your radio, then check all the control surfaces are set to neutral. Start the engine, make sure the model is held by someone or is restrained so it can't move forward. when the engine is running to your satisfaction,have your helper hold the nose up about 45 degrees,open the throttle and if the engine stops it is running too lean, open the needle valve a little, and repeat until it is running with the nose up. Point it into wind and open the throttle and be ready to correct any torque with right rudder. when airborne climb to an altitude that allows for any mistakes, reduce the throttle to about 3/4,
Don't let the model get too far away before you turn, and remember your throttle, cut it when you get in trouble to minimise damage.
But that won't happen. when you reach altitude, trim out the model, left right, up down, until it flies straight and level hands off.
Then it's time to land. leave yourself enough fuel for several approaches at a safe height, then when you are happy with the setup, try it down low. don't forget the little flair just before touch down. I hope this helps you make up your mind to try to find an instructor. But if not, I wish you all the best on your first flight.

Cheers,

Bill.