Trying to remove Chess.app using terminal
There seem to be several questions hidden in your post: 


You can‘t remove Chess.app (or any other of the applications installed as part of macOS) without disabling SIP. 
if you are short on disk space look for things which use a lot of space, not for small applications
rm -f is used to remove several files and ignore any errors which might occur
rm -r is used to remove folders and their content (recursively)