Cannot Retrieve Photos and Videos from MyBook for MAC

Hello. This is my first time using this forum and am not even sure if this is something anyone will be able to help me with. I have a MyBook for my MacBook Air. I take lots of pictures and videos and consequently need to regularly back my laptop up to this external hard drive and then delete the pics/videos off of my laptop after backing it up due to lack of space on my laptop. When I originally purchased the MyBook, I was under the impression that I would be able to use it almost like a thumb drive (but with the benefit of it having so much more storage capability)…would be able to store all old videos/pics on it and retrieve them later to view/edit. Anyway, I have religiously backed my laptop up and then deleted the pictures and photos to free up space (for several years). Now that I am trying to access some of my older pictures and videos from this external hard drive, I cannot view or retrieve them. I would ideally like to copy them from the MyBook and put them onto another laptop that has more space (and where I can view them more easily and potentially do some editing). I can see that backups have been made over time, so I would imagine it is all there. It is simply not allowing me to open anything which leads me to believe that the issue is ME and not the device. I would be most appreciative of any support anyone can give re: this. Thanks in advance for your time (and please know that I am not a very tech savvy person which is probably why this solution is not more obvious to me).

What did you use to create the backup?

Most external drives can be used “like a thumb drive” - but files backed up with an application sometimes need that same application to restore the data.

I’m not sure if this is the correct answer, but I believe Time Machine? I plug it in and that is the only thing that comes up, prompting me to back up that way. But, when I try to open what I have on MyBook, I cannot open anything. I would love to be able to open up each iPhoto program that was saved each time I backed up as what was in iPhoto changed each time due to my deleting things out of it after backing it up.

I think you can view the files in the restore option.