IPhone 4 - Deleting albums/pictures synced from computer?

I have no idea how to do it, can someone explain with simple instructions as I hate technology.

To delete photos from your device:
In iTunes, select the device icon in the Devices list on the left. Click the Photos tab in the resulting window.
Choose "Sync photos from."
On a Mac, choose iPhoto or Aperture from the pop-up menu.
On a Windows PC, choose Photoshop Album or Photoshop Elements from the pop-up menu.
Choose "Selected albums" and deselect the albums or collections you want to delete.
Click Apply

Choose from your synced photos