You can inject in the lower abdomen. Avoid the one inch area surrounding the naval or you can inject in the outer thigh.

Sterilize the injection area with an alcohol swab by cleaning about two inches of skin around the injection site. Then let dry.

Pinch the area of skin you have cleansed with alcohol. The injection is given here. Holding the needle like a pencil about 1 inch above the injection site, quickly insert the needle. Depress the plunger all the way, injecting all of the medication, and pull the needle straight out.
Never reuse needles or syringes

Dispose of the syringe in a biohazard container such as a Sharps container – or in an unbreakable plastic container such as a laundry detergent bottle that you can seal.