A directory tool is probably a good first step. After loading the directory, you could do a filter on one of the various date fields loaded by the directory. For files created on or after the 1st of the previous month, the below filter would do the trick. It subtracts 1 month from today's date, and the datetimetrim sets it to the 1st of the month.
Can you say more about the files? If they're all the same schema you could then use a dynamic input or batch macro to load them into the workflow.
[CreationTime] >= datetimetrim(datetimeadd(datetimetoday(),-1,'month'),'firstofmonth')
The issue with using the dynamic input is that the file used as the input data source template will always need to be from the date period we are looking at e.g. if we are looking at jan 2022 files then the source template needs a creation date in jan 2022.
The files are all in CSV format and have the same columns so should be the same schema.
Thank you
@cayladuplooy then a simple batch macro should do the trick. There are some great resources on the community if you're unfamiliar
One other thing thay comes to mind: if the filenames themselves have a date in them, you can read in all of the csvs with 1 input tool using a wildcard (\*.csv). Include the filename as a field and parse out the date to filter down what you need.