REFramework is overkill for a beginner, and overkill for such a simple automation. Best way to learn is just to start a new blank project and write it from scratch.
each SERIAL NO has attachment one, two or more. so how can i create a loop like it clicks on 1st Serial no then going back to another one then downloading the attachment.
This isn’t really a good way to do this. If there is a failure, you lose your place. If records are added to the list after you scrape, the automation won’t pick them up. It’s better to just get the first record from the table, process it, then reload the URL to refresh the list and get the first item again - assuming items disappear from the list after being processed.