you can use an iterator to ‘list’ attachments and then do a filter to only process the attachments which start with ‘Payslip’
also in regards to renaming you can do some regex to break up the original name and then piece back together using date format etc… @Bjorn.drivn did a great post on regex in make: How to use Regex in Make?
And here is a link to the string functions: String functions
Hope that helps!
Best!