I have to replace the windshield on my car due to a branch falling on it. I know how to get it out but could someone help me with putting it in? What do I need to use to seal it and make sure it's lined correctly?

Go to pep-boys or any auto store and purchase the proper caulking you would need for that..
Also, you will need clips to attach to your molding around the windsheild that will set in to the caulking before it dries..