There are roughly a billion ways to back up photos. I mostly use cloud backups and I have Google (I pay $1.99 a month), Amazon (part of Prime), and Microsoft (part of my 360 subscription) all backing up my photos automatically. It's easy-peasy and largely foolproof. The odds of my computer and all three of them failing simultaneously are near zero.
The more manual way of doing it is to plug in an external hard drive, USB drive, etc., and dragging and dropping the photos you want to save. Then you have to find a safe place to store the backup and then remember to back up any new photos. It's just easier to let the online services do it all for you.
If you already have Amazon Prime just install their Amazon Photos app on your computer and let it find and save your photos. If you've got an Android phone you've already got Google's Photo app on the phone. You can also go to their site on your computer and let it find your photos. If you've got a Microsoft 360 subscription for Word, etc. then you've got One Drive and it'll find and save your photos for you.
Those services are so fast and efficient that I'll sometimes take a photo. look at it for a minute or two, and decide I don't want it and delete it. One or more of them will have likely already backed it up and be holding it in that short of a period of time and I'll find my deleted photo there.
Fly!!! Eagles!!! Fly!!!