Hi Ruth, this is Kimberly here from landscape-solutions-for-you.
I recommend to my clients that they put down a grass killer first. This will ensure all the roots are dead. I also recommend to wait a few days up to a week, before applying grass seeds. If you have any extra dead debris, remove and rake out. Once you have applied the grass seed, make sure you get on a good watering schedule. This will ensure your roots getting established. Bales of hay spread over the seed will help hold down the moisture. Once you seed the seedlings appear, you can remove the hay. If you have a frost, go ahead and keep the hay on.
Thank you for taking the time to ask a question and feel free to ask any type of question for you outside investment. Have a great day!