Are you installing your secondary OS on the same drive or on a separate SSD?

Do terms like partition, file system and bootloader mean anything to you?

read up on Secure Boot and consider turning it off if you can. makes life easier generally

since I want to go from Linux Mint Debian Edition single boot, to LMDE + CachyOS/Fedora/endeavour. I'm doing this post to ask some questions:

Splitting a partition through GParted is relatively straightforward.

Boot into a GParted iSO with a thumb-drive, determine which partition you want to modify which is quite easy if you know the size of it, once you figured that out you should be able to shrink “Free” space to make room for your new partition which will house your new distro.

Debian is very resilient, I’ve swapped my SSD, GPU, Motherboard, CPU and RAM without having to reinstall the operating system, all it needed was to remove the old packages/drivers to then install the new packages/drivers.

Edit: I recommend all beginners to learn a tiny bit of BASH, whenever you distro hop like this BASH is what your “terminal” or “console” will typically use for shell commands, the main thing that differs between Arch, Fedora and Debian is package management (apt, yum, pacman, etc) and how software is installed.

If you need advice or suggestions feel free to shoot me a DM!