I'm not sure explaining shampoo one more time will be less confusing. You spray shampoo on the lawn and then water a full inch of water. In 2 weeks you do it again. As long as you use at least 3 ounces of shampoo per 1,000 square feet, you're doing it right.

Technically your soil is not compacted - it is hard. When you soften it with the shampoo it will become soft to walk on every time you water and will get hard again in a week (or weeks) before you water again.

I hear the crabgrass in the north is still in full swing. Spraying it to kill would be a waste of time and money, because it is about to die any day now. Crabgrass only lives when the soil and air are warm. You can rent a dethatcher and that will remove it. Other tools that will remove it are a power rake, slit seeder, or any other tool with vertical cutting blades. Set the cutters to go down to ground level. This will shred the crabgrass so you can blow it away or rake it up. Then put the seed down and start watering. You don't need straw or any other gimmicks.

Crabgrass is the result of a combination of things. One is thin turf. You are addressing that with your seeding this fall. Great!! Another is the soil being moist for too long in the spring. If you water ever day, or it rains every day, then the crabgrass seed will germinate. If you water deeply one time and let the soil dry out for a month or at least several weeks, the crabgrass will never get started. Also it helps to mow your grass at a high setting on your mower. I like the highest setting but others swear the middle is good, too. Tall grass grows deeper roots to resist drought. And tall grass shades the soil so weed seeds don't get enough sunlight to grow.