How to start?

nice question,

Frist of all, you need to know if is this what you want to learn for real.

Second, Basics:

Numeral System ( binary, hexadecima, octal):

http://en.wikipedia.org/wiki/Numeral_system

Full Text Notation	Abbreviation	Number Base
binary	bin	2
octal	oct	8
decimal	dec	10
hexadecimal	hex	16

http://en.wikipedia.org/wiki/Binary_numeral_system
http://en.wikipedia.org/wiki/Hexadecimal
http://en.wikipedia.org/wiki/Octal

Converting each other:

http://www.robotroom.com/NumberSystems.html