how to partition the disk when you get a computer

When you buy a computer, most of the time, there is only one partition. 

What you can do is:

1. Use the diskmanagement tool which is in your windows system.

2. Shrink the size of the volume, and then you will see some unformatted partition. 

3. create new partition from the unformatted partition. 

It's easy to do in windows. Else what you can do is using tools such as PQMagic.