WELCOME, I'm happy you quit cigs and chose to come to this forum. Everyone is different and have to personally make that choice to transition for themselves. A person can only say so much but, if that person doesn't want to quit then there's not much that can be done. You can vape around them to get them accustomed to vaping. Maybe offer them a puff or two when they are out of cigs. Slowly, you can condition them to vape.
As for your question. There are two different types of tanks in which I'm going to give you visual examples. One is a CE2 tank, looks like this:
Simply put in your juice through the top, put your drip tip back on and your good to go. The idea is that the silica rope that's attached will feed the coil/ceramic cup. Although, there are flaws to the design overall. Which means you might have to invert it, in order to feed the coil on there.
Another type is a carto tank. Which is the most popular now. You either buy pre-punched cartos or do it yourself. As with the CE2 tank. Just put in some juice into the tank and then vape away. When you take a draw. It automatically keeps your carto wet.
The last type of tank is something like an EGO-T tank. There's an atomizer with a separate tank that can be attached. Just pop off the top for the tank. Place your desired juice in there, put the cap back on, and vape. It's very simple to operate. Helps if you take primer puffs as well