Not a bother - I'm a complete Linux-nub myself

I'd say do this:

1) Open up File Manager
Click on the Internal memory card link in the left window.
Does Stuff show up in the list of content on the right hand side?

If it does - continue to step 3)

2) If Stuff is not listed in the right window it is most likely that you accidentally created the Stuff directory somewhere else - maybe under a different directory, etc.
You can spend some time digging around for this missing directory - or just create a new one. And since you are already in the file manager you can do that right in there by clicking >File>New Folder and create a folder on the internal memory card

3) So, we know that there is a folder on the internal memory card, at the top-level, named "Stuff" (or whatever).

4) Now launch X Terminal again

5) If you got rootsh installed run the command root

6) Your prompt should have changed to Nokia-N810-something

7) Now type in cd /media/mmc2
(note that you have to use forward-slashes (/) for it to work
ALSO note that you HAVE to put a space between the cd and the folder name

8) You should now be in the root folder of the internal memory card

9) issue the command ls -l

10) Scroll up, if needed, to ensure that you see your Stuff folder there

11) now do cd /Stuff
(and yes, it's case-sensitive so beware of that)

12) You SHOULD now be in the directory where you put the files you downloaded - so now execute the command(s) listed in the earlier posts - and do let us know how it went