Hi,
Once you have installed the vSphere SDK package, refer to the SDK readme document under the SDK folder. This will help you to understand the components in the SDK package and how to access the VI web services (refer developer setup guide) .You have options to write samples either in Java or C#. ( clients which accesses the vSphere APIs exposed at the ESX/vCenter server)
For writing the samples in Java, drill down to the general package(\samples\Axis\java\com\vmware\samples\general). The first sample to understand is Connect sample. This simply establishes the connection to the required ESX/vCenter server. You can then experiment with the VmCreate sample to create a new virtual machine.
For further clarifications, kindly refer to the API reference guide shipped with the vSphere SDK package or post a specific question regarding which you are asking clarification.
-Angela
