Download attachments from particular mail of Gmail in UI Vision. If it is possible then give proper reference documentation for that query.
Of course it is possible to make it but you have to create the code by studying the commands of ui vision.
There is nothing ready with ui vision you must first decide how to do this job, then you have to study the appropriate commands and create the code. In my opinion it is a fairly complicated job and therefore either you study a lot or you will need a professional who writes you a suitable macro code.
In your case it is web automation and desktop automation together