Yes, the external drive is just another location, just like a folder on your PC.
Scratch memory is the temporary space used by Photoshop to handle the files you are working on. You can select which drives are used as the scratch disk in the properties section of Photoshop. I can show you at the club.
Jojo, what I'd do is copy the older photos you are no longer working on to the external drive. Keep any you are currently working on, on the local PC hard drive. This will enable you to process faster, and, will also encourage you to backup your precious photos.
One other thing people don't tend to do is, have a good scan through them and DELETE any that you won't be processing, you'll be surprised how many out of focus, badly composed, test shots you'll have on there.
I managed to transfer the thousands of old photos to the drive (without help from the kids might I add!), two and a half hours of my life I'll never get back.
I did end up deleting whole files of footy photos that were rubbish
And I've done as advised and kept this year's photos on the PC... So now I can get cracking with Elements
Joanne
"Anybody can be a great photographer if they zoom in enough on what they love." - David Bailey