As Shakespeare famously wrote:
“To partition or not to partition that is the question:
Whether ’tis Nobler in the mind to suffer
The Slings and Arrows of outrageous single partition setup
Or to take Arms against a Sea of different partitions”
The more educated amongst you might have already discovered, that Shakespeare did not exactly write it this way, but the even more educated might have already guessed hat if Shakespeare were to use Linux, he might as well have written the famous lines in a similar fashion… Or probably not. For all we know, he would even be using a Mac…
So the thing about partitions is that you can mostly forget about them if you are not interested in more intricate system setups. The Debian installer has an automatic partitioning function, that can do all the hard work for you, while you sit and drink tea.
One important consideration is dual booting. Naturally, you might not want to completely give up Windows, and Debian can nicely sit on your hard drive alongside any windows installation. The thing is, however, that if there is no room left on your drive (which is most possibly the case if it was a windows computer before), you will have to do some manual partitioning, namely, you will need to shrink the Windows partition. This is relatively easy, yet introduces a minor risk, and a bit of inconvenience. The process will be covered in detail in the “Surviving the installer” article.
Be very careful when you resize or manipulate partitions. It is best to make a full backup, or at least a safety copy of your important or sensitive data in case you run into problems. It is highly unlikely, but the devil never sleeps (therefore the devil’s eyes are always red.)
It is also a good idea to de-fragment your windows disk (from within Windows), before resizing the partition.
Of course it is entirely possible that you want to ditch any other operating system currently installed on your computer (it would be a brave and noble thing to do), and in that case, you can just lay your fate in the hands of the installer and let it do everything for you, including partitioning.
If that be the case, and you could not care less about how partitions work, and what they are, and you sure don't mind losing all data from your hard drive, or you are just running e.g. a brand new computer, or have any other reason not to care a lot; you can skip this bit and go read about other concepts, things you'll need to know about before installing, if you are new to Linux. This would save you a lot of time, but what with knowledge being power and all that, you might still be better off reading through these bits first.