Hey man, have you ever shot up before? If not I'd strongly advise against it cause once you pick up that needle you'll fall in love, and its a bad relationship. We have an IV thread in here somewhere.. I can't find it for some reason. Just make an informed decision.
If you're going to do this anyway, only do 2mg since you're relatively opiate naive.
Wash your hands
Crush the pill into a fine powder in a clean shot glass or similar container. A spoon is a hassle and unnecessary
add CLEAN water. Boiled tap water is preferred if you don't have bacteriostatic water
Stir it around with the plunger (other end of syringe) and do not add heat!
Use cotton or a wheel filter. If using cotton, filter it at least twice
Clean the injection site with alcohol or soap and water
Tie off and find a vein. You will feel a little squishy spot popping up
Insert the needle, bevel up, into your skin and pull the plunger back a bit to form a suction
Slowly push the needle further until you see a spurt of blood in the syringe
Untie your tourniquet
Push the plunger SLOWLY, if its too intense just stop so you don't OD
Pull it out gently, clean the injection site and apply a bit of pressure to avoid bruising
Properly dispose of the items/materials used. At least put the cap back on the needle and put it in a soda can before throwing it away.
If I missed anything, please correct me guys.