For those who mix their own e-liquids, they buy just the nicotine. That's what you're supposed to dilute with PG (propylene glycol), VG (vegetable glycerine), flavorings, and sweetener. If you're buying premixed juices then you can just add that to your tank and vape, the nicotine has already been diluted for you.
There's a lot to learn when you start vaping but you've come to the right place. The people here are friendly and don't mind questions at all.
As Medic said above, I second his recommendation to get 18 or 24 mg of nic in your juices to start. I was a pack a day Marlboro Light (12 mg nic equivalent) smoker when I started vaping. My juice was 24 mg of nic so I could break the analog (cigarette) habit. Once I got over the hard part I started going down in nic. Now, I vape mostly 12 mg but go down to 6 and sometimes 0. It won't happen overnight but it'll get there.
