help with vape pen / e-pen?

hey guys and gals,
 
first off before i get a flaming, i know this is probably not the best place to post, but couldnt find an alternative. 
 
i don't smoke weed/grass or anything similar. but i am interested in how you manage to get a pen to smoke that haha. 
 
basically my enquiry is helping to choose a e-pen/vape. im new to the whole thing but i am just smoking the juice to get me off the cancer sticks. 
i have a basic £20 vape from my local store which isn't great by any means, it can do for now but i read a little on it and by everything i seen it is best to build you own.. in the sense you pick each part of the vape. 
 
can anyone explain what each part i need has to be, the differences and what to look out for.
different atomizers and such confuse me for example. i do not know the difference other than the look, and the compatibility is another mystery.
 
recommendations is also appreciated. like i said im just on the standard juices that you buy with them. at the moment 18mg. seems ok for now but lacking a little punch. 
 
also a place in the UK i can buy these parts from would be awesome but i can look that up myself given the correct thing to look for.
 
thanks for any help

 

i cant say i understand that, should i search for it. most of the posts ive read i dont understand. since i need it from the basics not telling me which atomiser to buy but not why it is good.. but point taken i guess ill keep searching i guess.
 
urgency has risen a little though since me and brother in law bough an evod e pen, my atomiser snapped off inside the tank for no reason and his battery came out the case pulling a wire out which needs soldering. reviews said they were not a bad starting e-pen and they both lasted less than a week.