Windows key mapping

[Thomas Blasejewicz]

Good evening
I would like to assign a number of keyboard shortcuts to the "Win key",
which is otherwise idle under Ubuntu.
I have Ubuntu 10.04 installed on an old note book PC (for experimenting)
and NO PROBLEMS to assign key combinations like "Win + U" = Logout.

Under TuxTrans (Ubuntu 10.04 + software for translators) this does not
seem to work. When I press the Windows
key in an attempt at assigning some shortcut, I get "ISO First Group"
and that's is - no combination possible.

Ubuntu help documentation -> http://Lin-transfer/MappingWindowsKey.htm:
"First, we will need to edit or create the .xstartup file. This file is
run when the GUI is started, and will give persistence to this
modification. If the file exists, open your favorite text editor then
edit to include the following commands. If the file does not exist, add
the following to a new file and save it to "/home/user/.xstartup".

# Make the Windows key a useable mod key:
xmodmap -e "remove mod4 = F13"
xmodmap -e "keycode 115 = Super_L"
xmodmap -e "add mod4 = Super_L"

Note: You can type these three commands directly in a terminal window to
test them. If the first command returns commandline:1: bad remove
modifier keysym list (empty), then simply delete it or add a # before it
to comment it out."

There IS no such file and creating it was possible, but when I tried to
save it as instructed, I red a red-colored error, telling me I do not
have the required permissions. I am the only one using this computer:

"Could not save the file /usr/.xstartup
You do not have the permissions necessary to save the file".

Anyway, I tried to find the "place" given in the instructions above:
"/home/user/", but using the find command I get NO results. (visual
checking / displaying hidden files = same result)
Do I have to CREATE this first???
I DID change the file permission (under properties for THAT file) to
read and write.
No change.

What am I supposed to do here?
I assume, I missed again something very simple but essential.

But then again, would it be possible to make these things/instructions a
little bit more user friendly, so that even people
can achieve these feats, who do not have a master's degree in computer
science ...