I'm using a vape pen and wanna to buy this mod. But I don't know anything about the coils and atomizers. Does coil and atomizer need to replace after few weeks of use? Where can I get another coil? I see that three different coils are in the subbox mini. Why three coils? And different coil if for what? And what about the atomizer? I don't know anything. Please help

I also see there is a cotton like think in subbox mini. Whis is this for? And the 1.2 ohm coils is for direct use. I mean open the packet and just use the coil or I need to open coil and setup it?