You can create two kinds of checkpoints, visual and textual. In addition, you can create variables from your checkpoints. For additional information on creating variables from checkpoints, see JS Methods and Tutorials.
To create a visual checkpoint, while recording a test:
Hover over the flag symbol on your recorder and drag the visual checkpoint flag to the desired element. Preflight will check your image and let you know whether the difference between the original image and the result is too large. You can change the sensitivity of the test using Max Allowed Difference % under Step Types.
Check Value/Textual Checkpoints
To create a checkpoint that checks a value or text, while recording a test:
Hover over the flag symbol on your recorder and drag the text checkpoint flag to your desired element. Preflight will check your text and let you know if there is a difference between the original and the results. You can change the value in the Value to check field in the Simple tab of the Editor (New).