Use a broad spectrum herbicide containing "glysophate". Mix concentrated herbicide with water in a sprayer. Kill lawn on a day when winds are calm. Put up warning tape. Read the instructions on herbicide label.
Take samples from all sections of your yard using a trowel. Mix the samples together. Put the mixed soil into a bag and send off to extension office for examination.
Measure the area to be seeded (Image 1). You’ll need anywhere from 1/4 to eight pounds of seed per thousand square feet. It depends on the kind of seed you will be using. A drop spreader works well along flower beds (Image 2). It drops the seed exactly where you walk. It doesn’t scatter or spread seed. A cyclone or broadcast spreader covers a wider area because it whirls the seed around as it spreads it. This is good for large areas. A hand spreader works best for smaller areas (Image 3). It’s light and portable. No matter what kind of spreader you choose to use, calibrate it properly, adjusting the number on the handle. To spread seed, walk up and down in rows, making sure you overlap the next row with the previous row to prevent bare spots. Lightly mulch with hay or straw over the seed (Image 4). Pull out handfuls of straw or hay at a time and scatter it over the seed. Spread out the clumps. Water the new seed. Water enough so that the ground is soaked. You want the seed to have contact with the ground beneath it. Don’t over water or the seed will rot. Plant warm season grasses in the spring. Plant cool season grasses in late summer or fall.