My abs light is on and my brake light is on and brakes go to the floor what todo on 1995 Buick Regal

My abs light is on and brake light is on checjed had no brake fluid added that then tried to drive it to get the brake fluid in the lines cane back let it sit and opened up brake fluid none again and none on the ground and brakes go to the floor i have no idea what it can be they do stop but no preassure ib the brake pedal i need thia fixed asap please help

Asked by for the 1995 Buick Regal
Add fluid again and have someone watch under the car and by the wheels for the leak. IF nothing external by the time the reservoir is almost empty , then separate the master cylinder from the booster and see if the M/C is leaking into the booster?
The fluid doesnt leak while it is sittig only while driving? And the brakes go all tge way to the floor.
master cyl. stayed full after pumping awhile?
Yea then i drove around the block and empty
Gotta be a wet spot somewhere! Did you check between the M/C & booster yet?