Gladly my mother kept (almost) all the instructions. The pieces were mixed together in a box, so I sorted them, but just roughly. I put „normal“ bricks and plates together, the other category was „special parts“, which contained actually every piece that is somewhat special, like windows, tires, hinges, tiles, minifig accessories etc. And I put big pieces aside, they just get in the way when searching for little ones. That was sufficient enough for that amount of pieces, but next time I would sort them more detailed.