I don't do tanks so I can't help you there. I use Boge 510 cartos (standard resistance is needed for slim 510).
Manuals batteries - press in 1-2 second before the start of your drag, continue dragging........ let up the button about a second before the end of your drag.. finish drag, inhale. I recommend on some inhales let your nose have some vapor. Much of the flavor is in the aroma (though I cannot find much nice to say about Chinese juice prefills)
Chinese juice is 100% PG base and PG lets through the most TH, irritation and flavor. Nicotine is a skin irritant. You might get sore tongue, throat, lungs. If your are bringing a lot of vapor into your nose (I do) watch for dry skin or irritation on your upper lip - just keep your face clean and use a bit of moisture lotion at night if it happens. Buy some better juice and tanks like 20-30% VG (correct?). VG adds more visible and persistent vapor and buffer the irritation and TH and flavor a bit at that level. Lots great juices makers - visit them.
Tank users can tell you if you should use a syringe to fill and if so what kind. Prefills will not last long unless you are a very light vaper.
I recommend you get a normal standard reisstance 510 atty, a 510 drip tip, some 510 carts. Drip tip on a normal atty is good for testing juices. Carts on a normal atty - will be useful if you run out of tanks and something else to try.
Over-niccing - If you are getting too much nicotine - more than you are used to - watch for headache, numb or cold fingers, rapid or irregular heartbeat. If you find yourself vaping alot more or more often than you smoked (common) you may want to try lower nicotine if you are getting those symptoms. I even vape 0mg sometimes (no TH but a good pacifier)
Drink plenty of fluids - vaping is more drying that smoking.
You may want to take vitamins few a few days. As your body adjusts to not having those 4000 other chemicals. I just felt a bit "off" the first few days.
Search for juices with aroma/TH/flavor that satisfy you. The search begins now. Some people need tobacco flavors in the beginning and get analog cravings from food flavors. I was like that. Others can vape any kind of flavor right away. Some stay away from tobacco flavors when they start and find that helps them. Depends on the person. Pay attention to how different juices make you feel. When you find one that makes you go Ahhh then that is a keeper!
Ok done editing