Update README.md

README.md

@@ -2,4 +2,20 @@
 ![Screenshot](https://github.com/cneud/ner.edith/blob/master/screenshot.png)
 
 - use mouse wheel to scroll up and down
-- use navigation << and >> to move faster
+- use navigation << and >> to move faster
+
+## Save to file functionality:
+
+The tool runs completely locally in the browser.
+Therefore it can not automatically save any changes you made to disk.
+You have to use the "Save changes" button in order to do that manually from time to time.
+
+If your browser automatically saves all downloads to your "Downloads" folder, you might want to configure it such that it asks you where to save it.
+
+Configuration option in Firefox:
+
+![Screenshot](https://github.com/cneud/ner.edith/blob/master/firefox.png)
+
+Configuration option in Chrome:
+
+![Screenshot](https://github.com/cneud/ner.edith/blob/master/chrome.png)