Backyard leveling

I have a slope backyard that is already high at the foundation so water will drain away from the house. I would love to have nice green grass. First, I would like to level the slop area. Can I use mulch to help level first then put top soil? Or should I just use topsoil? (is this cost effective ). Second, after leveling I would like to seed the lawn and plant hydrate plants around. Do I plant first then seed afterward?