A teacher training can quickly be spun up using a Course (aka a Training) or Semester (aka a Series).
Both options:
enroll customers into the whole schedule automatically; but also
allow for drop-ins (optionally)
allow for payment plans (optionally)
can be sold on their own (without the need for a membership)
Both options are publicly visible on your schedule and so should be named in ways that make them obvious to your end users (your customers) that they are teacher trainings.
What's the difference between the two?
A Course (Training) allows you to schedule its days irregularly (ex. Monday, Tuesday this week, Wednesday, Friday next week). Note that you will need to schedule each individual day though.
A Semester (Series) allows you to set a weekly schedule and choose how far out it will repeat, much like a college semester. (ex. Monday at 2, Wednesday at 5, through the next 6 weeks).
How to choose
So, in short if the schedule remains the same each week, go with a Semester (Series). If it changes week to week, use a Course (Training).
Here's how to create a Course.
Here's how to create a Semester.