How to add files to the File (Disk) type field in the activity in Bitrix24 business processes?

Question

Bitrix24

There is a list of documents where at the first stage when adding an element, in the field type "File (Disk)" I upload files. For example, at a certain stage of the BP, I need to add
files to this field so that they appear in the list by this type https://yadi.sk/d/YtckmGUCygMNhg
Disk)" and the files from this variable are appended to the document floor with the type "File (Disk)", but something goes wrong.
I try like this
Files = merge({{Files}}, {=Variable:files})
but something doesn't work I
tried like this