CandidateRecruitment inherits from System.FileDocument. System.FileDocument is the entity to contain the file content and every FileDocument can be downloaded when selected (add button in grid header). An attribute of type String cannot be downloaded (unless you add specific programming, not standard Mendix).
I can see in the image that you have already generalized it from the system document so the next step to download file double click on that one data row in the candidate recruitment page and you will get option for download.
something like this
hope this helps!