Beginner needs to do logon script in group policy

Can someone help me write a script? I need to track logon/off times & dates. Here’s what I know… I’ve seen some examples of what to put in notepad & save as a .bat file. Then, I know to go to group policy, & add it to the logon script. But then what? I don’t know if the script was written correctly or how to retrieve the results (I’ve never done this before).