Prepare short materials that cover most basic use cases either in visual documents (screenshots, diagrams) or video (we like loom.com as it allows for annotating and reacting to different parts of the video). Writing things down goes a long way.
Pair up lower-skilled employees with more technically savvy colleagues to help them solve specific problems and understand more advanced use cases. It might have a form of informal ad-hoc meetings, an organized mentoring program, or “open-hours”, where skilled employees make themselves available to answer any questions. If you can record these sessions, then technical gurus might just send a link instead of running the session again (if there is exactly the same question or problem).