What's standard business access equipment setup for fiber?

If this isn't the correct sub I apologize.

Long story short my companies moving, the new building has limited options on providers and we are looking at a smaller outfit for cost savings. I work for a small 10 person company and I've been put in charge of making sure we get up and running.

My main question is what's standard equipment and setup in the industry for connecting a new building or suite in a building? I know nothing is exactly a standard cookie cutter setup I'm just trying to make sure we have what we need to at least have internet going as we are on a super tight schedule.

My understanding from searching online, is with fiber whoever the isp is they run their wires through the building and provide an ont in the units server room, the ont will provide fiber to ethernet and coaxal connections. Instead of a modem you will use the ont connection to distribute internet?

On our end we would connect an ethernet cord from the ont to our firewall then to the main switch that distributes ethernet to all the wall outlets. We have an it company but they are dragging their feet getting back with me and I have a meeting week the low voltage sub tomorrow. (for our current equipment moving over we have a Wan/lan wired to sonicwall firewall which connects to a 10 port switch. On the switch is a tower server and router then returns to wan/lan)

The small scale internet provider has zero equipment listed in their contract so I'm trying to make sure we aren't missing pieces of equipment to be connected. When I brought up the equipment they recommended we buy our own modem/router. From what I have searched with an ont you don't need a modem? So I'm guessing they meant router or I'm missing a key piece of the puzzle