The brake fluid reservoir is part of the brake master cylinder, and is located under the front engine compartment lid, on the driver's side of the car. Check the fluid level each time your engine oil is changed.
FLUID RECOMMENDATION & LEVEL CHECK
The fluid level can be seen through the plastic wall of the brake reservoir. The levels in both the front and rear chambers must be above the "MIN" lines. If it is necessary to add fluid, remove the cover by lifting up on the tabs on both sides of the cover. Use only Delco Supreme No. 11 or other DOT 3 specification brake fluid and add as necessary. Clean any dirt away from the cover and plastic reservoir before reinstalling.