I am afraid I don't have the knowledge or skills to really know whaty I am doing

Hi kz3, this question is a little difficult to address out of context. It sounds like you are seeing an error message about having different versions open, or different profiles, or maybe there is an error referring to a version number. Could you explain what you are seeing in a little more detail?

In case it helps, when you posted, your Firefox identified itself as version 158.0.1. Coincidentally Firefox 159.0 was released today, but let's work out what is going on first before you try to update.