If you don't want to spray poison, there is a gentle method that works well: - Get a pressure sprayer and vinegar essence (very cheap in any supermarket). Mix 200ml of vinegar essence with 5 liters of water and then spray the weeds thoroughly on a day when no rain is expected. The vinegar breaks down very quickly biologically. The weeds will die within a short time. Only the pressure sprayer should be cleaned thoroughly afterward, because the vinegar attacks the seals and the membrane.
Furthermore, the new earth will also contain plenty of weed seeds that are just waiting to "come into the light". The best time to lay your lawn is actually now, since the "main weed season" is already over and without constant care week after week, the lawn will turn into a meadow faster than you can blink.
With regular mowing, watering, and fertilizing, much can already be managed. The rest can be dealt with by pulling or selective herbicide. A proper lawn is work. Before laying a new lawn, you can also use the bad Glyphosate. But it is actually not necessary.