You will have a fibre modem that converts the fibre to copper and then some kind of router, they do not have to be in the same location if you have a copper connections elsewhere.
This is my fibre setup. In a hall cupboard. We haven’t got structured cabling in here yet as its a flat and didn’t come wired for it.
Having some wired points is never a bad thing, in out house we have 8 in out TV area, 4 in the office and 4 in the bedrooms. All wired back to the loft where the phone line comes in and our router, switch and backup NAS drives are.
You have to decide the central point where they all wire back to, an office, broom / under stair cupboard, loft? This is where your router and switch will generally live.
If you have issues with wifi connectivity in other areas of the house, then you’ll need to look at ‘Meshed’ wifi solutions, I believe Netgear, Linksys andGoogle and BT all have offerings in this space now.