A submission is a snapshot of your project, usually processed for grading.
In Review mode, you can:
View statistics about your current project, such as the number of task runs
Load previous submissions using the Review button next to a submission
View the task and check results of previous submissions
View the read-only snapshots of files at the time of a previous submission
The grade for a submission (if any) is determined by multiplying completed tasks by their respective weights.