To avoid scalping, the grass should not be allowed to grow too long before mowing!!!!!
Lawn may be mowed once the roots have taken hold. Check by trying to lift the rolls and ensure your turf has a tight bind to the soil. (If the rolls have not even slightly taken root within 2 weeks then something may be wrong with the soil)
Keep your lawn below 1 inch - never remove more than one third of the leaf.
For best results keep mower blades sharp.
Mow your lawn weekly for ease of maintenance.