You want to divide up your hard disks yourself so that you can determine the data structure.After you have set up your system, keyboard and time zone,
the data must be written to the hard disk, so you must select "Choose exactly where RebornOS should be installed" on the following screen.
Press the right arrow
In the next screen you will see the hard disk (here a VirtualBox virtual hard disk).
If you have a new hard disk you must now create a partition table where you must decide whether to use msdos MBR or the new GPT.
Here I use msdos MBR and create a /boot/efi partition with a size of 100 MB. In this partition, the boot loader GRUB is installed,
which starts the system.
Now we have to create the data partition/partitions, we actually only need the / partition (the so-called root partition) that contains the system.
There are a number of ways to design the system, here are the possibilities shown in the menu.
/boot/efi and / are enough for me, I continue with the right arrow key in the installation.