A training course might not show in School > All Staff > Staff Development > Training Courses > Course Attendance.
If you click into your training course from the All Training Courses page, it won't show under the Course Attendance page if the setup looks like the screenshot below.
This is because an event hasn't been created for the training to take place in. When a staff member is marked down as attending the event, the Training Course should show. If you need help creating a Training Course correctly, take a look at this article.
Make sure the Training Course has this additional section showing a date and time. Then any staff under the Persons Attending Course section will show on the Course Attendance page for that course.