First of all, at the beginning of the program in CTL, you can import some of the existing programs in CTL. The way how you must do it is as follows:

You must decide whether you want to use single or double quotes. Single quotes do not escape so called escape sequences. For more details see Literals below. For these fileURL, you must type the URL of some existing source code file.

But remember that you must import such files at the beginning before any other declaration(s) and/or statement(s).