Following a tutorial introduction to Perl/Tk will help you get your program going. You can try perldoc Tk::UserGuide or Tk Tutorial, Featuring Your Very Own "Perl Sig/OBFU Decoder Ring" or google perl/tk tutorial.

Start by copying the programs exactly as they are in the tutorial and get something working. Then you can make changes to make them they way you want them. Until you are familiar, it will probably be easiest for you to make one change at a time and then test, being sure to keep a copy of your last working version. If your program stops working after a change, then you know where the problem is and can easily go back to the working version and try again.

When you have specific problems, read How do I post a question effectively? and post your code with a description of what you expect and what actually happens.