Automatic Disk Partitioning

Hello,

I've been used to install (as dual-boot) RHEL 7.2 on my computer that has archlinux OS already installed along with the disk containing 3 partitions: btrfs(boot), ext4 and an empty one (free space) which is considered to be the installation's destination. Being afraid of losing any of my data, I would like to make sure of the 'Automatic Disk Partitioning' installation step's safety against any data loss, and whether it uses only the free space from the disk.

Thank you.

Best Regards,
Kais.