top dressing...compost

i have an area about 40 X 40 and want to give it more vigor to accept grass seed........top dressing..what is that...where do i get it, how much do i use, how is it prepared........it will be used over part of a lawn that is crab grass infested........thanks

If you add an inch of compost in the early spring or early fall, you will gradually improve your soil - making it more hospitable for desirable grasses. 

great.......i'll do it in the fall..........how do i spread this compost.........and after this application, do i seed on top of the compost........thanks

Wheelbarrows and rakes will be your primary tools. 

I wouldn't mess around with grass seed unless you have a bare patch that is bigger than two feet across.