The “classic” installation method is to create a “live” media into a bootable usb stick, then boot into said stick and install Fedora 39 into the internal SSD.
Unfortunately I run out of usb sticks and I’m going to install Fedora into an external SSD, then install said SSD into my FW13. However, the Fedora image from the official website are “Live ISO”, when using it has no username or password to set, prompt the installation or “try it out” every time upon boot.
The question is that how can I download and burn the non-“live” version that are ready to run on the target SSD immediately after burning the image.
I cannot write you a solution. I myself would proceed by trial and error. But here are a couple of path I might try to follow.
If you are using another computer with an installed OS and your future FW13 SSD connected to that computer then you may try to install fedora using a VM. Pass your fedora ISO as a disk and pass your SSD to your VM. Fire it up. Install fedora to the SSD.
Another way might be to create a small FAT32 partition on your SSD. Copy there the content of your fedora ISO. Find the bootable EFI executable. Move the SSD to the framework. Boot the iso EFI executable (using the “boot from file” bios option). Install fedora (you will not be able to touch the FAT32 partition you just created). Reboot. Wipe you the iso FAT32 partition. Maybe format it to be used as swap.
I installed Fedora on 250Gb expansion card. Convenient since it illuminates the need for cables, external SSD, etc. Could you temporarily free a USB to create installation media? You only need it for the installation.