Is it flashing with the key on run position? Flashing in off position is normal, like for an alarm. Clutch down when starting, I am sure you are doing that

My neighbor's Taurus had a battery you couldn't jump. It could be the starter is stuck. Maybe, take a socket extension and rest it against the starter motor, and give it a light tap with a mallet. Do the dome lights go dead if you try the starter?