I have a 93 ford tempo. my car does not start when i turn the key. i am wonderin how to jump the starter posts?

For weeks now i have had to get under the car and tap the starter with a hammer or stick, and then the car started fine. I was careful not to hit the starter too hard because since I am not a car whiz, I google'd how to do it properly. Earlier today my car wouldnt start and I did the same process, but still the car didnt start. I took a screwdriver and placed it near the starter wiring and the starter made a whirrrring noise. so i dont think its the starter. I appreciate step by step details on how to jump the posts. Thank you