When you choose to have a Step contribute to the learner's progress, learners will get a grade/acknowledgement for both the Step (and its Course) when they've completed it!
To ensure they get those scores and grades, checkmark the following statement in the Step's configuration panel (in the Step wizard):
Depending on the Step's type and configuration, learners will either get a percentage grade or a completion mark when it's completed. In the example below, the Human Step is configured to only register whether the learner has or hasn't met with their mentor, compared to a MultiChoice Step which will always give a percentage grade.
Note that if the contribution box isn't checkmarked, learners won't get graded at all!
A special note regarding the Link Step: the contribution box cannot be checkmarked at all due to its simplicity. As such, Link Steps cannot add to the learner's grade nor offer a general completion mark.
As for how scoring and grading works for both Steps and Courses...
Step Scores
learners earn a percentage grade in each Step
earned each time a learner completes a Step
contributes to their final Course grade
abandoned or incomplete Steps will remain "incomplete"
"incomplete" Step score is given if a learner loses all their lives
Course Grading
learners earn a letter grade in each Course that contains at least one graded Step
if a Course contains only ungraded Steps, the Course won't show a progress indicator/grade
grades are awarded as soon as they've completed all graded Steps within a Course
grades improve as better scores are achieved in included Steps
only the most recent Step scores counts