с нуля(Our courts system is complicated and – in places – confusing, because it has developed over 1,000 years rather than being designed from scratch.4uzhoj)
переделать заново(When I sent out the request to Atlanta I noted that the RT549-01 series was very similar to something we'd already built, and so the whole thing didn't need to be redone from scratch as parts of it were actually identical. -- поэтому всё не нужно было переделывать зановоART Vancouver)
начать всё с самого начала(to start (an activity etc.) from nothing, from the very beginning, or without preparation • He now has a very successful business but he started from scratch)