During the Prepare disk space step in Ubuntu desktop installation, you'll have a choice whether to use the guided - use entire disk which is going to automatically assign partitions for you or to create the partition manually. Let's make it clear so you know what option to choose.

If you choose the first option, Guided, Ubuntu will automatically create all the partitions needed to install Ubuntu and assigns required mount points. The benefit is you can skip all the hassles of doing hard disk partitions. Reduce some installation times and great for Linux beginner who just want to try Ubuntu. The draw back is you have to accept whatever partition size that has been assigned to the hard disk.

If you choose to manually partition the hard disk, then, as the name suggests, you need to create all partitions and assign the mount points yourself. The benefit is you can customize all the partitions and plan what to do with hard disk space. For example, if you want Ubuntu to be a Linux multimedia workstation, then you can freely assign larger space to /home partition. This is what every Linux users do and love, to customize the system to your personal needs. The draw back maybe you need to spend some time to create hard disk partition.

Choose the latter if you want to partition the hard disk manually. Don't worry, this is the purpose of this tutorial. You'll be fine.

This is a free space that you have in your current hard disk. Click on the free space to create a new partition. You can create a new partition by clicking on the New partition button.

The swap area has been created. The device name or the partition name is /dev/sda1. Click on the free space to create a second partition. Normally, the mount point that should have their own partitions are the /(root) directory, /home directory, /usr/local/ directory and /var directory. We are going to create / partition as the second partition.

The second partition which is the / partition has been created. The device name is /dev/sda2. Now we are going to create the third partition for Ubuntu desktop. The mount point remains are the /home directory, /usr/local/ directory and /var directory. You can choose whatever mount point that you already planned. In this example, we are going to create a partition for the /home directory. Ubuntu desktop uses a normal user account by default, so assign an independence partition for /home directory is a good choice. What I mean is all users' home directory in Linux is created by default in /home directory except for root user (administrator) which has separate directory called /root. By creating a dedicated partition for /home directory, we don't have to worry about data missing each time we upgrade Ubuntu.

If you ask what is the right partition size for /home directory, nobody can give you the exact size. It depends on your hard disk space and the usage of your Ubuntu system. As mention earlier, you would be using a lot of /home directory space with Ubuntu desktop. So give a large possible space for /home directory is recommended.

Click on the free space and then click the New partition button to create the third partition.

If you are going to create more partitions for Ubuntu desktop, continue as we did before. When you finished, you can see a summary page like this and this is the final step for you to revise the partitions. You can cancel all created partitions by clicking the Undo changes to partitions button to start create a new partition all over again. When you satisfied, then click Forward button to continue Ubuntu desktop installation.

That's all. Good luck and have fun with Ubuntu!