Automatic partitioning allows you to have some control concerning what data is removed (if any) from your system.
To remove only Linux partitions (partitions created from a previous Linux installation), select Remove all Linux partitions on this system.
To remove all partitions on your hard drive(s) (this includes partitions created by other operating systems such as Windows 95/98/NT/2000), select Remove all partitions on this system.
To retain your current data and partitions, assuming you have enough free space available on your hard drive(s), select Keep all partitions and use existing free space.
Using your mouse, choose the hard drive(s) you want to install to. If you have multiple hard drives, you can choose which hard drive(s) should contain this installation. Unselected hard drives, and any data on them, are not touched.
You can review and make any necessary changes to the partitions created by automatic partitioning by selecting the Review option.
Select Next to proceed.