Eudy doorlock s330 installtion help!

I spent 2 hours in the cold trying to get it working so forgive me if I mistype. Got the new lock and was excited to have it up on the door. I removed the existing deadbolt. Out the eufy deadbolt in and was screwing the faceplate thing that holds the deadbolt in place . Few questions.

1.The faceplate is not flush into the door . I am assuming I'm going to have to file some of of the sides to have it fit in ? Is this the right way to do it.

1. One of the 2 screws just stripped randomly while the one I put on top went in smooth like butter. Can I use any screw whichis similar length ? Or should I order some replacement .

2. Can I just use the faceplate and the strike plate from my previous door .

Thanks and hopefully someone can help !