Same way you do from the first really. You have to inj the same amount of air into the vial as you intend to draw out, or there will be a vacuum created in the vial. After drawing from the first, turn the
syringe upside down and get all the liquid down onto the rubber part of the plunger. bring the plunger back to the level you want to draw from the second vial and stick the
needle in the vial (still upside down). Inject the correct amount of air, and draw the liquid from the second vial. I usually pull the plunger back 1/2ml farther from the amount I actually want and pull the
needle out when the liquid reaches 1/2ml. Later