How to Work DNS- DNS Process

Basically its work on IP to Name and Name to IP . For any example like Yahoo.com
First- Client will request to his own dns server
DNS server may have ip of yahoo.com if yes. it will resolve ip and send back to client if database is not there then it will ask to its upper DNS server, if that server will have data it will responce with ip otherwise it will refer to another server root dns server is after that there so many upper layer dns like
.com
.org
.edu
.cz
.uk
after then suppose under .com there will be so many domain
like yahoo
google
orkut
msn
and so on and after than connect successfully.