RAID only makes sense with multiple disks
so that you MIRROR (RAID1) or SPREAD (RAID0) or both (RAID10) your partition on two or more disks
you really need to start by understanding the basic blocks before trying to use them.
RAID is a really good feature of modern OSes but it requires redundancy of hardware to be enabled.
single disk installation will not do.
and search articles for LVM too.