Are we talking about managing a disk (i.e. a hard drive, or SSD) or Manipulating it?
Managing it is usually no problem. But when it come to Manipulating it, That's a different story all together.
That is something better left to the professionals, and they have written some pretty good software to make the job so a little easier.
Still, it requires SOME knowledge of the RULES, for one to be successful.
For instance, you can't make one partition on a disk larger, till you've already created space, by making another partitions smaller.
Simple things like that have been the undoing for many a beginner.