Well if you have a needle that is long enough, you would attach it to a syringe. Clean the xyphoid process area with betadine and alcohol. Insert the needle just beneath the xyphoid process, aiming it left towards the most distal corner of the scapula (straight line). Insert slowly, until you strike blood, then use syringe to suction off the blood.
Obvioulsy, IV access, oxygen, sedation, and a cardiac monitor should be in use.