Tall fescue is best planted in the fall. Since fescue seed does best when the soil temperature is 50 to 65 degrees, the longer the seed can germinate in cooler conditions, the better. Planting in the fall gives it two cool seasons--fall and the following spring--to get established. Spring is the second-best time. Summer planting isn't recommended; though fescue is heat-tolerant, high heat can make it go dormant. That's fine for mature grasses, but not good for new growth.
If you're planting an entirely new lawn, or just a bare spot, loosen the top couple inches of soil to give the seed a proper bed for germinating. If you're trying to thicken up a spot where the grass has gone thin, start by giving the area a good going-over with a thatching rake to pull up all the dead grass; the seed has to be able to reach the soil, and it can't do that if the lawn has a thick layer of thatch. If you're overseeding, cut the existing grass short and then run a thatching rake through it before applying the fescue mix.
In a small area, you can just spread the seed by hand. For larger areas, load the mix into a broadcast spreader and push that around according to the package directions. However you get the seed down, Scotts recommends that you follow up with an application of Scotts Starter fertilizer, then lightly rake the area to work the seed and fertilizer down into the dirt.
Water the new seed frequently, but not for long periods. You want it to stay wet, but you don't want to drown it. Keep watering it regularly until the seedlings are two inches tall. Add some Scotts Turf Builder Fertilizer about eight weeks after the seeds sprout. Mow the grass when it reaches mowing height. To keep the lawn looking good, overseed every fall.