Hi Linda, welcome to Scrap Girls! We are so glad you are here and happy to answer any questions you have. Someone more knowledgable on some of your questions will post soon but I'll do my best to answer what I can.
I believe many of our customers use Photoshop Elements which is less expensive than Photoshop. I'm sure the other gals will have more suggestions as well.
EHD is an External Hard Drive - It is used for extra storage for your computer. You could store your kits here until you get a computer if you wanted.
All the digital products would be downloaded to your computer.