To create and format a partition (volume) Two methods

  1. The hard way

  2. The easy way

1)The hard way When you create partitions on a basic disk using Disk Management, the first three volumes you create will be formatted as primary partitions.
Beginning with the fourth volume, each volume will be configured as a logical drive within an extended partition.
For more information, see
What are partitions and logical drives?

1.     Open Computer Management by clicking the Start button Picture of the Start button, clicking Control Panel, clicking System and Maintenance, clicking Administrative Tools, and then double-clicking Computer Management.Administrator permission required If you are prompted for an administrator password or confirmation, type the password or provide confirmation.

2.     In the Navigation pane, under Storage, click Disk Management.

3.     Right-click an unallocated region on your hard disk, and then click New Simple Volume.

4.     In the New Simple Volume Wizard, click Next.

5.     Type the size of the volume you want to create in megabytes (MB) or accept the maximum default size, and then click Next.

6.     Accept the default drive letter or choose a different drive letter to identify the partition (I like to use a letter between S W So your  USB devices stay in the lower range letters), and then click Next.

7.     In the Format Partition dialog box, do one of the following:

         To format the volume with the default settings, click Next.

8.     Review your choices, and then click Finish.

(102,400MB for a 100GB partition)

2)The easy way MiniTool Partition Wizard Free is to manage the hard drive partitions on your computer. Tasks such as copying, resizing, deleting, and creating partitions. Also includes a handy OS
migration wizard that allows you to migrate to a larger hard drive or a speedier SSD drive.
Down Mini Tool here

 MiniTool Partition Wizard Help