If there are other partitions that you need to delete, like recovery partitions in use by the previously installed operating system, now is a good time to remove them. You probably only have one of these auxiliary partitions, and probably only if you had a previous version of Windows installed.
For example, in Windows 8, Windows 7, and some Windows Vista installations, a small recovery partition, labeled here as System Reserved, is created and populated automatically during that operating system's installation. The same thing will happen behind the scenes as you continue to clean install Windows 8. However, you no longer need the one installed by the previous Windows installation so you can remove it.
To do so, repeat the same process you followed to remove the primary partition in the last few steps:
Highlight the partition you want to delete and then touch or click Delete.
Note: You might notice that the first partition we deleted appears to still exist. Look closer, however, and you can tell that it's gone. The description now says Unallocated Space and there's no longer a partition Type listed. In other words, this is now empty space, which we're getting close to putting Windows 8 on.
Important: Again, make sure you're not removing partitions you don't really want to remove. One of these Windows auxiliary partitions will clearly be marked as System Reserved and will be very small, probably 100 MB or 350 MB depending on the version of Windows that you had installed.