Getting started:
The new HP Prime graphing calculator has a somewhat steep learning curve.  If you are thinking about purchasing an HP Prime or recently acquired one, I would suggest you spend a little time with the following guides available from HP:  HP Prime User Guides

Short HP Prime modules:
Here are short modules which introduce HP Prime applications or functions.  In each, I'll provide a few worked examples, keystrokes and HP Prime screenshots.  You may want to browse these modules in the order listed as I give fewer keystroke hints later on.   Feel free to ask me questions through link at bottom.

Solve() function      solve(), substitute()
Define User Functions, Function App     User functions, Function App, copy/paste
Spreadsheet App, CAS Calculus     Calculus performed in Spreadsheet App
Statistics 2Var App: Manual and MAKE Data      2Var Statistics app manually and using MAKE()
Statistics 2Var App: MAKELIST, L1 and Spreadsheets     More ways to create, analyze data in Stats 2Var App  

New - curve fitting, analysis comparing HP Prime to TI36X-Pro

HP Prime & TI36X Pro: Part I - cubic curve-fitting 
HP Prime & TI36X Pro: Part II - cubic curve analysis

Coming soon - handy things the Spreadsheet App can do...