Once you know the engine, you can then consult a repair manual specific to that engine and year of Blazer. A repair manual (either physical or online) will provide pictures and precise location details. Searching online for "[your engine type] 2001 Chevy Blazer camshaft sensor location" will likely yield helpful results with diagrams.
Generally, the CMP sensor is located on the engine block, near the camshaft, but the exact location varies significantly depending on the engine design. It's usually accessible without major disassembly, but checking a manual is crucial to avoid damaging other components.