I would contact the county extension office (if there is one) where you live. They might have advice for what you're wanting to do. That's what I did, but I live in Kansas and the grass where you live is probably not the same.
There is also an organization called the Alabama Turf Grass Association that might have some advice.
https://alturfgrass.org/
The basic steps to replanting a yard are:
1. Do it at the right time of year for where you live. (Late summer for me; may be different for you)
2. Kill it, with something like Roundup.
3. Rake off the dead grass.
4. Till it, but not too much.
5. Spread seed and starter fertilizer
6. Rake lightly to cover seed.
7. Water.
8. Water, mow and fertilize as needed for your location.