I have installed 3 times of Kubuntu. But I think automaticly, kubuntu creates 3 partition of hard disk. My disc is 20gb. But I dont know the partition names of harddisc. For example, when I was using xp, I create 4 gb for C, 16gb for others. While formatting harddisk I just erase c partition so I cant loose datas on D. I want to do it on Kubuntu.

While installation I want system to take 3 gb, 500 swap and rest is for etc. How can I do that? Thanks

I don't know why you want a separate partition for /etc
Though, you will need at the very least a partition for /

Don't have Kubuntu automatically resize the existing partition. Choose to manually edit the partition table and resize partitions as you see fit.

This guide is written specifically for dual-boots, but it contains step-by-step instructions on how to go through the install process and select partitions to resize and install on:

http://users.bigpond.net.au/hermanzone

But I dont know what they are, for example /etc, /usr /,

there are lots of directories inside and I dont know exactly what they are.

I have given an example on windows, if you read it again I think you will understand what I mean.

For example I was using C drive on windows, for operating system and programs and games.But Drive D was for my secured datas, pictures, musics, documents etc. I want to do it on linux.
ex. for system: 3gb (but what is it name on linux)
for documents: 16 gb (but what is it name on linux) ex, is it /usr ????
swap: 500mb

This is what you want, then:

3.5 GB Ext3 /
16 GB Ext3 /home
.5 GB swap

/ is the "root" or top-level folder that contains all the other folders. This will contain everything, including programs and whatnot.

The separate /home partition will show up when you click on the /home folder on the / partition. "/home" will just be a pointer to the actual partition--it won't be a folder on the / partition.

If you're used to Windows think of /home as a "shortcut" that is really linked to your 3.5 GB partition.

The advantage of this setup is that if you happen to screw up your Ubuntu installation (or if you simply want to do a clean installation of the next version), you can do so without affecting your data files and settings and preferences.

thank you very much for your detailed information.