A repair manual (either a physical book or a digital version) will provide detailed diagrams showing exactly where the thermostat housing is located and how to access and replace it. Without that visual aid, pinpointing the exact position is difficult and trying to find it blindly could lead to damage.
Searching online for "1997 Buick Skylark 2.4L thermostat location" along with images might provide some visual clues, but relying solely on this is not advised. A repair manual is the safest and most reliable method.