You should be entering these commands from a command prompt.
The output.txt will be in the folder that you executed the command from.
The > output.txt at the end of the command will redirect all the output to this file rather than to the screen. This will make it easier to capture the output and post it here.
If you want to see if the command is executing anything, you can run the second command and leave off the > output.txt. You should see quite a bit of information show up in the command window.