Advice on marketing hyper-local b2b startup

Hey, we're launching an office catering startup in Toronto, ON. To refrain from being self promotional I won't share its name or URL but rather, I'd like to share a general idea of what we're doing and get some collective wisdom from you.

The idea is partnering with local restaurants and catering companies to be the "Uber for Office meals". What does this mean? It means that we can do volume orders, e.g. orders with a minimum required order amount of $150, and a minimum required notice time of 24 hours.

With over 15 restaurants / catering companies signed up with accounts (listings) with great offerings. I'd like to gauge the best way to market this and sell it. Given that it's a "hyper-local" marketplace of restaurants and catering companies offering "platters" essentially, what's the best way to get people using it and trying it out?

And then to provide more general advice, the take-away here can be applied to almost any hyper-local, b2b focused startup.

Thanks! Looking forward to engaging with you.