This article describes the process of framing a floor during new home construction. The floor is built on top of the sill plates that were installed before the basement walls were built.
The sill plate bolts will often come in contact with the rim joist. The wood needs to be cut out around the bolts.
Floor joists are typically laid out at 12 or 16 inches on center. This picture shows both. The side closest to the camera is 12 inches on center and the farther away joists are 16 inches on center. The closer together the joists the longer the span of the joists and larger the room in the basement.
Bay window floors are framed by extending the floor joists over the foundation. The joists must go back into the floor system 2 to 3 times farther than it cantilevers out. The small joists on top of the foundation wall in between the long joists are necessary to hold the wall that may be above.
Joist hangers are used to hang a joist when there is no bearing wall beneath. Construction adhesive is used in the seat and on top of the hanger to reduce the chance of floor squeaks. You can see the glue oozing out of the bottom of the hanger.
This is the floor after it is sheeted with 3/4" oriented strand board. The sheets are staggered like bricks to provide additional strength.