Debra is right on
If you want all your hard work to last you will pay a professional to do it for you. This is not something you should attemp after reading about it on the internet. Maybe the professional mechanic will show you how to do it so that you can decide if you want to pay him to do it again next time too. I'm all for saving money and becoming self sufficient by doing you own boatwork, but this is not something you do on your own the first time.