As mentioned before, the Kepler - Attachment fields | simple & multiple custom field can be configured to store multiple files.
Step 1: Click on Attach files Icon 
and select files.
Step 2: Choose one, or multiple files from the opening window or, drag and drop your Files.
Step 3: At this step, you can:
1. Delete files from the custom field.
2. Preview images or download other file types
Step 4: The Attach File Manager controls automatically the attachments according to the administrator's configuration, and displays error messages in case of files that do not correspond to the field configuration.
Case 1: Files extensions are different from the configuration.
Case 2: The sum of all sizes is greater than the defined one
