Brake light stays on the dash board

It may be from a leak in the brake hydraulic system, or it could be from normal brake wear. As the brakes wear, the fluid level in the reservoir drops slowly and needs to be topped up regularly. If you topped it up and the light is off, and the brakes are operating normally, then drive it and if the light comes back on take it in to have it inspected for a leak. I bet it was normal and there's no problem.