http://www.sosuave.com/articles/6secrets.htm
You don't really need a video... It's straight forward.
Head held high, shoulders straight(Working out helps this a lot!), feet apart while standing and slow movements.
When sitting down just focus on being relaxed and comfortable it's that simple. Sitting back: Sit back, relaxed, not stiff or rigid. If you want to sit forward rest both elbows just behind your knee joints so your arms don't fall towards the ground if you're not locking your fingers(Like this
http://blog.blacksocks.com/wp-content/u ... orward.jpg ) then knot your fingers in a loose clasp(Interlock your fingers loosely like the guy in the picture). Keep your head forward and high without causing strain as you do this. If you do this while sitting forward your back will naturally straighten and become more pronounced. It's very "alpha" body language, naturally relaxed and demonstrates confidence, success and high self-esteem.