This is just an example. You need to create the files yourself. (You'll see your example refers to "file:MyApache2/CurrentTime.pm").
mkdir -p example-lib/MyApache2
touch example-lib/MyApache2/CurrentTime.pm
Then paste the contents from the example into the file you just created.
In order for this to run under mod_perl, you'll also have to let the server know where your MyApache2 is located. You should be able to add something like this to your Apache config:
PerlSwitches -I/path/to/example-lib
Don't forget to restart Apache before you test this out.