We suggest not walking on your grass at all, until it has had a substantial amount of time to root and grow. As the grass will most likely stay dormant in winter, the recommended time frame of 2 - 3 weeks (in the summer time) does not apply.
Walking on your lawn after a frost is a big no no. When walked on, your grass will start to snap, effectively destroying the cells and killing the leaf. The grass won’t be dead, but you may start to see irreversible black patches.
If you absolutly have to walk on the lawn in the first 2 - 3 weeks of it being laid down, please use a plank of wood to walk on so no dents from boots / shoes are left.