Tutorials for kick-starting the development in MPLABX is available in Microchip developer Help website. Visit http://microchip.wikidot.com/mplabx:start
There is a self-paced training course for MPLABX is available at: http://microchip.wikidot.com/tls0101:start
And useful videos are available at : http://microchip.wikidot.com/tls0101:videos
If you’ve installed MPLABX and XC8, use this tutorial to create your first project: http://microchip.wikidot.com/tls0101:lab1