well, its all pretty easy. the resistance of your atomizer determines how many watts you get for the volts you put in. So the variable wattage or voltage batteries you see, basically just have an adjustment to make the vapor stronger, with bigger clouds.
For starting out, I recommend getting a variable wattage battery, whatever kind you choose, and make sure you get a tank that has adjustable airflow. That is an adjustment on the tank, that allows you to control the tightness of the draw. all the way open is almost like an open breath of air on some tanks, and the smallest setting is like a really tightly rolled cigarette. You will get a lot of advice, brands etc that mostly depend on people taste, and what they are familiar with.
I would recommend first, going to a brick and mortar store, and seeing if you can try a few devices, and find out what you like.
I recommend this for a starting kit, although there are a few out there....this one is pretty good bang for it's buck. That is actually one of the tanks I use, and I love it.
If the kit below was out when I started vaping, I would have quit the cigs first time. I started with weaker, starter ecigs, and went back on the smokes, this is what I needed to get enough vapor to get off smokes. Since then i have a sub ohm setup I use, but that is the next level.
Aspire - Aspire Premium kit consisting of nautilus mini and VV+ battery
Sub Ω
So in a quick nutshell, the coils for the nautilis mini, and a lot of other tanks out there, the atomizer resistance (ohms Ω) is 1.6 or 1.8 Ω. When you go to 1 or below, its called sub ohm. These tanks generally have way looser draws, and are better in my opinion for direct lung inhales.
So basically, I went from some crappy ecigs, to something like the kit I linked you to, to the sub ohm unit. Lots of people don't like sub ohm, and stick with something like the kit, some people stick with something less, it's all personal preference. But with something like what I linked to, chances are pretty good, that that you would be set for a while, and get an enjoyable vaping experience, which isn't always the case with the lower end starter stuff.
it is so important that people start with decent equipment, and don't judge the vaping experience with sub par products.
DISCLAIMER: there may be some slight errors, this is a simplified explanation for beginners, and I tried to break it down. for example, I have an atomizer with a 3Ω coil, and I'm sure there are 2Ω out there, but you get the point I was making.
Here is a video about the Ω's:
wow really appreciate buddy