Attaching resume?

Some schools like Brown allow you to attach a resume. Is this recommended? Doesn’t the common app basically have everything on your resume already? But then I heard attaching a resume would allow you to elaborate more on your activities. So should I put the same list of ECs on the resume and elaborate more and upload that? Or just not upload a resume at all.

No it’s not recommended. In fact, it’s discouraged. It’s just more paper and yes, everything is already in your application. There’s even space in the Common App for ‘additional information’ if you feel you need to elaborate on something.