How to configure single servers to existing farm servers?

How to configure single servers to existing farm servers?

Hi,

In my farm , we have 2 WFE's & 2 APP's , 2 CQ servers. Now i need to configure one more WFE & APP server to existing farm.

Could you please let me know how to accomplish this. i have to install & configure fast search server to the farm.

If we install & configure Fast search server to the farm. then we can dismantle existing crawl/query servers from the farm..

Badri