off the top of my head, making sure that the building rent was paid and maintenance and supplies taken care of for various offices, managing calendars for the executives, managing software licenses, doing any government paperwork that was needed, perhaps even doing the admin side of HR if there're no dedicated HR roles.

As far as I know, our CEO does a lot of this sort of work himself. There's just not very much of it so far. We only have one office, we don't license much software, and we pay a company to manage employee benefits.