The download button will appear in the customization screen. See [[Customize Firefox controls, buttons and toolbars]]. If not, it's already on the toolbar somewhere. Check the '''Overflow area''' to make sure that the download button isn't hidden there. If you do see it on your toolbar when you are in customization mode, but not when you are in regular browsing, it may be set to automatically hide itself if there are no downloads in progress or completed. If you click on the download button in customization mode, there should be an '''Auto-hide''' checkbox that you can use to enable or disable this feature. If all else fails, hit the '''Restore defaults''' button at the bottom of the customization window to refresh the Firefox toolbar layout. Hope this helps.