I think I did everything right and I do the next step (1b, 2a....till3b) but the grader seems can not get my grade.
Sorry you're stuck but there's almost always a pretty easy fix! Do NOT try to start all over again, uninstall Max's Pitch Package, etc. That can make it worse. There's a 95% chance the same snag/fix is listed & answered in the Help FAQ. But if you can't find it there, post your problem here.
Make sure you post in the right category below & be sure to include a screencap showing the issue!