Please follow these steps:
1. On the Firefox main menu bar, select ‘Tools’ and then ‘Options’.
2. Scroll down to the ‘Files and Applications’ section.
3. Set the ‘Downloads’ option to ‘Always ask you where to save files’.

Now when you use Save Page WE:
1. A popup window will open with two options: ‘Open with’ and ‘Save File’.
2. To save the file, select ‘Save File’ and click on ‘OK’.
3. A 'Save As' window will open allowing you to choose where to save the file.