Collect PDF attachments from multiple emails and combine them with cloud convert

Hi, how do I go through multiple emails, collect the PDFs and combine those PDFs with Cloudconvert? I dont quite know what parameters to set or how to map the data. I am always getting some sort of error, no matter what I try. Thanks!

I conclude from the error that the input only contains one file.
I think that with ‘input files’ not a single file but the whole array must be entered.