Hi Motoman.
If the atomizer is brand new, you may wish to put about 4-5 drops into it and activate it. Take a puff but immediately blow it out without inhaling. After about 4-5 puffs, add another 3-4 drops of liquid and repeat this process a few times. All atomizers are different but this will make sure any residue from the manufacturing process (which may yield a weird taste/smell) has been burned off.
Atomizers are different, their resistance is different and the
devices they are used on are different. Therefore, the very general rule is about 3-5 drops and that should yield about 5-8 good puffs.
After the first 2-3 puffs, you will notice a slow drop in
throat hit, vapor and perhaps flavor. Those are the first signs it is time to add another 2-3 drops. If you start getting a harsh feeling in your throat it is definitely time to add more drops. If the liquid begins to taste bitter or like it is burning, it is also a very clear sign to add more drops.
On the other hand, if you hear a gurgling sound, you have added too much, too soon. Take a few puffs ( until taste and throat hit are good and gurgling stops) to burn off the extra liquid.
All the best!