Where are the child anchor points in a 1998 5 door sentra

Bolting in child seats is rather old fashioned since a range of child seats arrived on the market that are designed to be retained by the vehicle's own seat belts.
These seats are easily swapped between vehicles, are safe and secure and widely available.

I haven't needed to bolt in a child seat for nearly 20 years but I used to fit many for my customers. It was invariably impossible to piggyback the upper strap mounts onto the vehicle seatbelt anchor points and new mounts had to be drilled after removing seats and trim. Sometimes it was possible to piggyback the lower mounts. So far I haven't encountered any car with pre-installed child seat mounts.

carefully look at the deck covering for impressed lines as that will indicate where the cover has been weakened to allow easy removal for the anchor bolt
depending on the seat in use there could be one directly behind and in the middle of the seat or one on either side of the seat position
look up from in the boot and see if there are nuts welded in place already for seat belt anchor points

yes the rear parcel shelf has plastic clips holding it in place take one of these out the left one usually and the child anchor bolt you get with the seat goes straight into it same thread and all

If power windows and the same window does not open the child safety switch is a very good possible reason.

There are no child anchors on a 96. This was around the time the latch system was under development. Just went through looking into this for my 1996 van. chico car seat fit well

The newer van seats will not fit either( I do have a 2007 seat for sale now ) as I tried to make one fit in my 1996 van with the latch system and it didnt fit. Wheels right spacing too wide for the anchor points.
Tom K. MN

I’m happy to help further over the phone at https://www.6ya.com/expert/james_da451a4ec470352a

could be one of the switches may be faulty. They'll either be located on the latch anchor point or within 2 inches of the anchor

The rod that connect the latch to the handle has become disconnected. the door panel needs to come off. You should see a rod hanging helplessly away from the actual latch mechanism. Using the point that the rod is still attached to as a center point... rotate the rod and look for the plastic connector for the rod to reconnect. This will be a small plastic part with a clip that secures the rod in the anchor point.

no ,too early

The rear seat child restraint anchors were not required (by law) until early 2000's. Most likely your car does not have them.