Briefing
The flag is several directories deep. Instead of cd-ing one level at a time, let find do the walking:
find . -name flag.txt
Then cat the path it prints.
Objective Locate the file named flag.txt anywhere under your home directory and read it.
Stuck?
Take it one step at a time. Ask for a hint here, or type help in the terminal to
see the commands this challenge is about. Typing hint works there too.
That is every hint. If you are still stuck, run help in the terminal.