I wanted to make my clients website <snip> CMS based, how can i do that please suggest us.
Look around and check the reviews of different CMS software. Decide which one is right for you; then find a template you like and customise it.
First of all you need to know that which CMS you want to use..Most popular are Joomla and wordpress...both are easy to install...Go to there official website they will tell you each step in detail..:)
first of all it depends upon you, which one is best for you, but in my point of view you should go with wordpress, easy to install and you can easily customize it in your way.
The OP asked how to install CMS but hasn't returned to say which CMS