I looked and don't have any decent pictures of the mounts,
I used two caravan minivan seats, middle and back seats, they are front facing right behind the drivers seat, no space between them, you have to step over them to get to the back of the bus,
I used two rows of 2x8 boards, all were 7.5 ft long, I believe the front most stack was 3 deep and the rearmost stack of boards was 4 deep,
The minivan seats have legs of sorts but they are taller in the front than the back which is why my board stacks are different heights,
The hardest part is drilling the main bolt holes from the bottom of the bus, they had to be through the cross beams and sized for 3/8 inch bolts, each row of wood got 5 grade 8 bolts through the cross beams, an additional 5 bolts per stack went through the floor sheet steel, these bolts went through some additional 2in wide by 12in long 12ga metal strapping which acted as a long thick washer of sorts,
Again, do a lot of measuring before you start drilling to make sure your seat placement allows for enough bolts connected to enough sheet steel or cross beams.
The car seats dont have mounts for bolts, the metal that acts as legs is basically flat and not L shaped so you will need some type of angle brackets to connect the bolts to the seats,
It would be much easier to find bus seats that have legs ready made for bolts and that are tall enough so you dont need to raise them higher but if the seat did not come originally with a seat belt attached to it the seat may not survive a rapid deceleration or roll over intact, bolt the seat belts to the floor frame separately from the seat.
Each seat got a 2ft section of 2 ton chain, when connected the chain is in a U shape, 2 bolts connect it to a different floor frame and each end is bolted to each chair leg.
I purchased new lap seatbelts and bolted them directly through the floor into the cross beams.
A 37ft bus like mine is unlikely to receive a severe deceleration event unless it hits a bridge or does a header into another large vehicle, roll overs dont create the same extreme instantaneous forces that a regular size vehicle absorbs when it hits another vehicle.
My opinions, take them for what you paid for them.