questions about my analytics

i first want to say thank you as this sub has been nothing but helpful and instrumental to my forward progress. I have learned more here in such a short period time than i ever did at 'higher learning'. This is my first post here seeking guidance but I hope that my second post will be my contribution!

I have read plenty of post, articles, and blogs about SEO and google analytics (Moz ftw). So while I understand the terms that are used I am having a hard time putting them in context to my own reports. I have been trying to adjust my search to maybe find some content that could put things into a more detailed perspective.

To be more clear as to what I am asking: what exactly does/can your overview page actually tell you about your site?

eli5 google analytics overview page?