linux - How do I create yum repo file?

I know there is a previously asked question, but I still have some doubts so asking again.

How do I create a yum repo file?

I know that in the /etc/yum.repos.d/ I have to create .repo file. Below is the pattern:

1 [name ]

2 name=

3 baseurl=

4 enabled=1

5 gpgcheck=1

6 gpgkey=

Here in the baseurl which link should I give? I'm fully confused about this. How do I get that baseurl link? Can anyone please explain to me clearly?

I am using CentOS 6.2.