The only thing you need to think about in this case is, in which directory you are on your computer.
Your command line window shows C:\users\rei0d\desktop\
as your current directory.
So the only thing you really need to do is:
Remove the desktop
by "going up" with the command cd ..
.
So the complete command would be:
cd ..
ping XXX.XXX.XXX.XXX -t