When I forget where I saved a file, I use "Save As" and the last used folder opens up, and if I sort the files by DATE, I will see the file I saved last.

The other way to find the file is to determine what the file extension of the file is, say it's a csv file you saved.

I go to MENU then it says "Find" and I type in csv and all my csv files will pop up, that's in KDE Linux and  Ubuntu is similar.

Here's a page from Ubuntu wiki: https://help.ubuntu.com/community/find

If you don't have a "find files" program, use the Ubuntu program installer and  install one.  catfish is  one.  

v73

David N1EA