The concept of binary file is for static files, like images, templates and they are generally stored in /webwb folder of server.
If you requirement is just to upload and download from enduser UI, perform the steps below:
-Place FilePath control in the section where you want to upload file.This set file path to a property
-Create an activity with java step to convert the captured filepath to fileInputStream and further to byteArray. The stream can either be written to certain location on server or can be encoded and stored in DB.
-Refer to @baseclasss.DownloadFile for downloading file from server.