Use the Add Partitions launchpad to guide you through the tasks necessary to add partitions to an instance. The launchpad also helps you assign the newly added partitions to database partition groups in the databases that are in the instance, and then redistribute data in the database partition groups.
You should backup all databases in the instance before and after redistributing data in database partition groups. If you do not back up your databases, you might corrupt the databases and you might not be able to recover them.