Preparing soil for lawn and borders

Appreciate your advice here. Having recently tackled a mass of brambles, nettles and other weeds, we are trying to start preparing the ground for its next chapter. It will be part lawned but we’d like to establish some colourful borders. As you can see the ground is very uneven and full of stones and pebbles. I’d read rotovators can be helpful in clearing a big space but not if there are stones as they jam. Is a tiller more suited? Having never used either am looking for some guidance. Can anyone recommend a suitable tool that would help us level and anything that would not break as we try to remove them? Thanks in advance