The block "Here's Your Next Training" is already added by default in the Single Training course page. This is a block used to have a logical order through your trainings for the students.
Here's the explanation of how this block displays the next trainings for the students:
The block will always show the Next Available Training that the student has not completed yet (check off all the points of the training is considered completed), this means that if a student completes all the course, the block will dissapear since it doesn't have anything else to show.
So, what happens if you have blocked content? The block will show the content in the following order:
Old to New Released Content.
Old to New Blocked Content.
This means that if the released content is already completed by the student and if you have some blocked content besides that for the student, they will see the oldest blocked content in that block.
Here's an example of this:
If I release Training 1 and Training 3 for a student, once they complete it, the block will show Training 2 but locked. This is how they will see it:
If you add more content later that is available for the student, the student will see the new content released in the block instead of the blocked one, this applies only until the student completes the released content and they start seeing the blocked content again in the block.
Example:
If I add the Training 4:
Once the student unlocks that training, they'll see the new training released instead: