Under the vehicle on the frame rail just about directly below the drivers door area.
To replace you relieve the fuel pressure, then use a flare nut wrench to loosen the fuel line nut.
Now use a small bar (brake adjuster tool works pretty well) to pop the brake, return fuel line and vacuum line loose from the plastic bracket holding the fuel filter.
On the other end of the filter is a quick disconnect fitting. Just blow out any crud or use a small pick to make sure there is not dirt in the connector clip. Then squeeze the two ears in to unlock the connector. Release the connector and remove the inlet metal fitting nut. Have a catch container ready because there will be fuel leakage.
Remove the bracket from the old filter and install it on the new filter, watch the positioning. Then reverse the procedure.