HOA Condo Solar Installation

I'm the board president of a small, 5 story/32 unit building.

Our average solar bill is like $600. I've done preliminary research and have shown that we can get an affordable system that could take care of our power needs.

What are some things to consider when trying to get something like this going?

We have a flat roof and all units pay their own power so the solar would likely just be able to go to the common areas.

Has anyone successfully installed solar on their buildings?