It is easy to add a single file upload button in the MDriven Designer, but to handle multiple files you'll have to create a component.

A typical case is that you want to make it possible to choose a couple of files together with other information about some entity. Here we will have a project and add a multiple file upload for documents.

The model for the example is a project with some documents. Each document holds the file (a blob) and a filename (a string).