There are several options for viewing a list of the exercises you've performed. From the Statistics tab, the following options are available:
Selecting one of the History fields presents you with exercises in the View range (see Statistics for information about View ranges). You may further filter the exercises presented to you by choosing a Workout, Category or list of Exercises.
Whatever way you choose to view your history records, they will always be presented in the same fashion:
If multiple sets were recorded for an exercise, the cell will have a slate-blue background. You may touch the record to reveal or edit the individual sets.
If only a single set was recorded or the exercise does not track sets, the cell will have a white background.
Touching on a cell with a white background will bring you to the "Edit" page for the record. You may change any of the fields of the record. Be sure to touch the blue "Save" button at the upper-right corner to save any changes you make! Pressing the "Back" button will leave the record unchanged.