Step 1

Find and select the folders you want to backup, e.g.

- Documents
- Music
- Pictures
- Videos

Step 2

Click with your right mouse button on each folders and click on 'Properties'.

Step 3

Amongst other properties, you will see the size of the folder in MB's or GB's.

Step 4

Type the size of each folder below. Click 'Add folder' below to add up more folders.

GB (1000 MB = 1 GB)