I am increasing the volume in my Synology DS209j NAS

Currently 1tb in Raid 1

Do I just put in first new 2 tb disc and manage it from within DSM (4.2)or do I have to "prepare" the new disc first?

The prepare process looks longwinded and not what I thought would be required. Any help with this would be appreciated. 

The Synology help page at http://www.synology.com/en-global/support/tutorials/560 (point 3) reads: 

 

Replace hard disks for SHR, RAID 1, RAID 5, and RAID 6:

 

 

1. Turn off your DiskStation (skip this step if your DiskStation supports hot-swapping).
2. Remove the outer casing from your DiskStation.

    

   Important:
   To avoid harming yourself or damaging your DiskStation, please follow the hard disk installation instructions found in the Quick Installation Guide for your Synology product.

    

3. Replace one of the old hard disks with a new one you have prepared.
4. Turn on your DiskStation.
5. Login to DSM with an account belonging to the administrators group.

But it is not web linked to a specific process so I am unsure of its requirement.

Cheers for any advice.