I am not sure about Tennessee, but consult your local farmer's almanac, or check with a local nursery. Tall Fescue aka Marathon, Medallion is a transitional grass, therefore not cool season nor warm season. I have been a nuseryman in So Cal for 20 yrs. or so. What I would recommend is to prep your soil via rototill and add amendments such as redwood and fir compost. If you have a heavy clay soil, add gypsum as well. Rototill as deep as you can. Add approx 1 cuyd of compost per 500 sq ft. Mix it all together, and then get a water roller (bigger than a beer keg) to compress it all back down and get the air pockets out. If you are not in a great big hurry, start irrigating and grow up all the weed seeds. Once they are all sprouted, shoot them with Round up. I like to deplete the weed seed supply, otherwise it will come right up with your grass. Roundup is very earth friendly and does not toxify the ground at all. Once you get a good kill on the weeds, rake it off, and then apply the seed. I do not want to recommend what type of seed to get for your area, consult a KNOWLEDGEABLE nurseryman in your local area. I love blue grass, but the heat out here takes its toll. It may be perfect for your climate, I do not know. Good luck, and yes you are on the right sub forum. I am sure the guy who was rude will learn to read the stickies eventually.
I almost forgot, cover your seed and keep moist til it is up about a 2". Do not be in a hurry to mow.