Can you provide a bit more information? When you say the soundfonts don't show up, do you mean the ones already loaded on your saber, or ones that you've downloaded?
Downloaded soundfonts should be unarchived and placed in a folder, then you use the Obsidian launcher to browse to the correct folder.
Emory has a video that explains how to use the launcher to change soundfonts, and I'd recommend watching that if you haven't already done so. It may be an older version of the launcher, but the process is the same.