Obay, make it easier for everyone by searching the forum for Scrapebox threads, reading through them, then asking more specific questions. It's hard to help if all you ask is "Can you give me a rundown of what Scrapebox does?" since the answer to THAT question can easily be found by going to their website.
For deeper stuff though, you're going to have to read... get a good foundation in functionality, evaluate you own situation and think about ways that the functionality can help your specific situation then ask question more for clarification on those particular points.
For instance, some people use it to ping their articles for increased viewer counts - if you're not using article marketing though, their point of view on usage wouldn't be helpful to you.
Basically, the thing is that noone's going to hold your hand through Scrapebox - it's not what the forum is here for, it's not realistic to ask, and it's not fair to people's time to expect it either.
The MAIN thread is like a million pages long, so maybe don't start there. A good one is the one titled "How to make the most out of Scrapebox" or something like that.