Well assuming you have the new window follow these steps
1 have windshield on hand
2 have windshield sealant on hand
3 have new rubber gasket if possible
You can buy steel wires specifically for removal or heavy fishing line
Remove rubber gasket around windshield.
Then use small screw driver or small pry tool to slide between windshield and car frame.
Then use wire or heavy duty line (wear gloves) cutting through sealant on on window.
Remove old clean off old adhesive lay new adhesive In appropriate spot with suction cups lay in new window add more sealant and reinstall rubber gasket allow 24-36 hours for full cure depending on temp and humidity