HA! Your English is fine! My French is completely imaginary!
Or as Google would say:HA! Votre anglais est très bien! Mon français est complètement imaginaire !
Firefox is famous for making updates and your version may be older than mine. However, in version 116.0.2, the images below show where to find the settings for making the app "ask" (allow) you to save a download. Firefox, at least in this version uses a regular tab to link to the actual settings for the app. What it calls "settings" is what we Mac users call "preferences".
The settings shown in the last image will/
should cause a standard "Save" dialog to appear whenever you download something. You can then rename the download or change the download location.