The front one.
Assuming this is a V-8, Chevrolet's #1 cylinder would be the first one in front on the drivers side bank.
Drivers side front
The number one cylinder on any 4 & 5 cylinder is the cylinder at the front of the engine. On a GM V6 & V8 it is the front cylinder on the driver's side.
The location of number one cylinder depends on the manufacturer of the engine. For example, a Ford 302 and a Chevrolet 350 have number one cylinders on opposite sides.
if it is a 4 cylinder the number one is the first cylinder behind the belts and all that stuff. If it is a v6 the number 1 cylinder is the first cylinder behind the belts on the bank closest to the front of the car.
It starts on the side of the engine where the number one cylinder is. This varies by manufacturer, fore instance Chevrolet's number 1 is on the driver side Ford's number one cylinder is on the passenger side.
One for each cylinder, six in a six cylinder, four in a four cylinder.
The cylinders are numbered 1-4 from front to back so number 4 will be the closest one to the transmission.
The firing order for a 1996 Chevrolet S10 Blazer is 1, 6, 5, 4, 3, 2. The number one cylinder is on the front right as you face the engine.
Assuming you meant 4.8 L, #1 is drivers side, first one in front.
Number one cylinder is the cylinder on the far right (passenger side in US).