Click the floating plus icon and select "Image Step"
Click on "Take Snapshot"
Enter a title, description and click "Save"
If you want to perform any activity on the screen and want that screen to be captured at a certain delay, you can use the delay capture feature
There are two delay capture options - 5 and 10 seconds
Either option when selected, starts a countdown for you to perform the particular task.
You have to make your best guess for how much time you will need
Your screen will be captured after the delay!