How to add path of a program to $PATH environment variable?

Firstly, check your original path:

echo $PATH

It should show something like this:

/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games

Now add your program to that path, ensuring your using the entire path all the way from / to your program.

export PATH=$PATH:/path/to/my/program

This sets your PATH variable to the existing PATH plus what you add to the end. Check that it has been added:

echo $PATH