This might help you. Someone got help with using the terminal. You use: cd to change directories. You can probably press tab for it to automatically show your directory options based on what you typed. To open a log, you can use: nano [file name]
I think it would be easiest for you to take a screenshot, but maybe there’s some way to transfer the log in order to paste it here. Actually Ctrl + Alt + F6 is the way to return to tty6, the GUI. Once you have the error log, you could make a github issue… I don’t think anyone mentions using the WWAN slot to install Qubes there. Does Qubes let you try out the the desktop environment with some default apps while installing, like Ubuntu and other distros? If so, you could probably just use a browser to copy and paste your code.
Have you installed Qubes successfully with an SSD in a caddy? I actually did install Qubes before on a T450s with this storage setup. I had to use the “dd” option when formatting the USB with Rufus instead of the “iso” mode.