How do I work on only one channel at a stereo file

Yes, I know it’s stupid, but I cannot find it in the manual

Split the stereo file into two separate tracks.
The tracks may be joined together again after, if that is what you want.
http://manual.audacityteam.org/o/man/splitting_and_joining_stereo_tracks.html

My programme is in Danish, and I cannot find anything called “split”, but can you tell which number it is from the top of the track drop down menu, thanks

Now I installed in English, but I still cannot find “Split channels”

0000.jpg
This is what my screen looks like

Look at the link that I posted - there is a picture.

I have look at it - but look at my picture
Can you see any “Split channels” on the picture, I uloaded?

This page: http://manual.audacityteam.org/o/man/splitting_and_joining_stereo_tracks.html

You need the “track drop down menu”, not the “Tracks” menu: http://manual.audacityteam.org/o/man/track_drop_down_menu.html

I DON’T KNOW, where the Track Drop-Down Menu is

Found it,thanks