Remove sidebar in ""post", header color and recent post

First of all, I live your theme very much! Its much more easy to used compare to others.

I have 3 questions to ask…

1. Why my “post” page have sidebar? How could I remove “archives” and “date & comment”?

http://massivedynamic.com.my/product/weighing-components-system

2. Could I change the header color to white?

3. How could I remove the “recent post” in my homepage?

Thanks in advance for the assistance.