How can I properly lay sod next to existing grass to ensure a seamless and healthy transition between the two?

To properly lay sod next to existing grass for a seamless and healthy transition, prepare the soil by removing debris and loosening the top layer. Lay the sod tightly against the existing grass, ensuring the edges are flush. Water the sod thoroughly and keep it consistently moist until it establishes roots. Gradually reduce watering as the sod takes root to encourage the roots to grow deeper into the soil.