Sending one PDF is easier than sending five. Here is how to combine files cleanly.
Rename files with 1, 2, 3 at the start, or add them in the order you want. The merged document follows that order.
Open the merge tool, add your PDFs and download one file. Check the page count of the result before you send it.
Merged files can be large. If the result is too big for e-mail, compress the images in the source files first.