Subpanel

Pretty good articles and video help:
How to Install and Wire a Subpanel by Ask The Electrician
http://ask-the-electrician.com/sub-panel-electrical-wiring.html
How to Wire a Subpanel by klowny1969 https://www.youtube.com/watch?v=suf9F2Hev50
NEC Subpanel Code Inspection Tips by softcellelectrical
https://www.youtube.com/watch?v=0rV1f0egkFk
How to Install a Subpanel by askmediy
https://www.youtube.com/watch?v=bDuOVe19C8M
DIY Electrical Wiring Workshop Electrical Panel by scottpdotnet