The easiest way is to shrink a partition or remove an unused partition, so that you get free, unpartitioned space on the disk (the Windows partition manager can do that), then let the installer use the free space to create the needed partitions automatically. It may be possible that you have already 4 primary partitions on the disk (many laptops come in that configuration), which will prevent the installer from creating new partitions if you don't remove one. We will know that if you post the the partition layout. You can get the exact layout with running
from a Linux live-medium.
Moderator note: Since your question is not really related to the thread you posted in I moved your post to a new thread.