Linux Mint (Ubuntu).

I'm looking for a way to encrypt some of my external HDDs. I was looking this option over -> but I'm not sure how well this would work. I read this on the top portion of the site -> "It is a pass-through filesystem, not an encrypted block device, which means it is created on top of an existing filesystem." What exactly does that mean. I also noticed that the encfs program (encfs) mounts to the encrypted/decrypted directories and since I will be having to mount an external HDD it looks to me like I would have a standard mount to the external HDD to my encrypted direcotry and then another mount from encfs to the same directory. Will that even work? Or, does anyone of any other suugestions or recomendations? Thanks.

Thanks, I'm also trying gnome-disks but it's taking forever to format my extern so I'm sure it's even working. I'll check that out. Thanks again.

Macrium Reflect (free) has a disk clone option.