Where does new owner find condo association trust documents?

I recently purchased a condo in a 6-unit building. My brother was the former condo association manager, and I bought the unit from him, so I am taking over as the manager. We went to the bank to change the owner of the association account and they said we needed condo trust documents or some documentation that I was taking over. They hadn't asked my brother for this when he took on the job, so we're not sure what to provide. Does anyone have a template or know what needs to be included? Can it be a simple letter? the association is pretty laid-back (i.e. lazy) about documenting these kinds of things. Thanks!