Welcome to ECF, Suze!
I smoked for 30 years, about a pack a day, maybe a little more. When I first started I was using one of those ones from a mall kiosk that looks like a cigarette. (It was a gift from my husband.) Once I realized that this was going to work for me I started researching and landed here.
For the first week I gradually cut way down and then had to make a conscious decision to quit. The first few days after that were a little uncomfortable, but definitely tolerable. I had previously tried cold turkey, weaning myself off, hypnosis, nicotine patches, nic gum, etc. Using the e-cigarette (I prefer the term personal vaporizer, or pv for short.) was nothing like any of my previous quit attempts. It was something I could do and it was relatively painless. I've now been smoke free for eight weeks! For me, that's a miracle! And I never thought I was going to have to kill somebody.
I would recommend you read the forums, especially the library area. There are some great threads in there that will help you understand this whole process. Don't miss DonDaBoomVape's six part series, "The Wonderful World of Vaping."
After my first cigarette looking pv I switched to a 510. I got tired of the battery life of those and got some eGo's. (The eGo's are also a 510, but with a better battery.) If I had it to do over, I'd avoid the initial frustrations and go straight to the eGo. The other thing you'll need are some good e-juices. My favorites come from Tasty Vapor, but Ms T's, MadVapes, and others have really good stuff, too. Lots of reviews here and all are users just like you and me.
Last thing, keep trying, and ask questions. This group will get you through any difficulties. In fact, this is one of the best forums I've ever been part of, everyone tries to help. (Well, maybe not everyone, but most everyone!)
Good luck!