I have never bought a Home theater system before.

I want to buy Bose speakers Lifestyle 35 and add another center channel and if needed another two for the center side channels

Which one is better 5.1 Vs 6.1 VS 7.1 VS 7.1 Vs 11.2!!

Can I use my own receiver preferably Yamaha RX-V3900 and use the DVD player that comes with Bose... help on set up

11.2 is 11 speakers and 2 subs, May be just what you need.
5.1 and 7.1 work fine.
5.1 is front and rear, a center and a sub.
7.1 is front and rear, a center and 2 side speakers.
Money and space may be a factor.