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.