When you are recording actions for a custom process step in a test automate, you press the “Read” button on the recording panel in the following situations:

To capture a value in a text field that should be stored as a variable. This allows you to reuse the value in other steps or test cases, or to compare it with an expected value1.

To capture text in a message screen that can be used for data binding later. This allows you to extract data from the message screen and use it as an input for another step or test case2.

You do not press the “Read” button to capture an error message or a static label on the screen, as these are not values that need to be stored or used later. Instead, you can use the “Check” button to verify that the error message or the label is displayed as expected3. References = Using the Test Automation Tool for Automated Testing - SAP Learning, How to get started with the Test Automation Tool for SAP S/4HANA Cloud Public Edition, SAP S/4HANA Cloud Test Automation Tool- FAQs Blog Series #1.