The side holes can be found by removing the sill plate and peeling the carpet back a little. They will be towards the back of the front seat, hope that makes sence. You might try looking under the rear seat for bolts, incase you don't have any for the front.
Seat belt mounting points are really obvious, check under the car. They are very strong mounting points, not just holes in the sheet metal. They need strong mounts and top notch fasteners to be strong enough to do their job. The same goes for the seat mounting points. They are reinforced from the factory so the seat doesn't go flying with you in an accident. If you mod or move any mounting points, be sure to do your own reinforcing and use heavy duty fasteners with oversize washers. Dave