It really depends on how bad you have it. My yard got pretty bad so it was tough.
I used a pick ax to remove all of the clumps. You can spread the work out over time.
Grass be gone bt ortho will kill it, but it will also kill other grass around it. This is good for spot treatment when you have manually removed most of it.
keep the grass short to prevent further spreading.
I had to dig part of my yard up and just replace with new sod and spot treat any coming up.
If you are looking for an easy way there is not one.