Program is a bundle of multiple courses which are generally required by trainees for completing a specific skill based training. E.g. program can be used to create a bundle of courses which a new hire employee has to go thru in any organization.
Programs are defined in a group, so just go to the program Tab of any group, and click on New Program. You can select any course which is authorized to the group, or to the whole site and add it to the program.
Courses in a program may have pre-requisite courses
Courses in a program may have pre-requisite courses which may be in different programs
Programs are delivered by creating Program Session, which is a timed instance of the program for a specified time period.
Further Reading: Creating Programs