You do it a bit like a brick wall, so the joins between turves are staggered, not forming straight lines across the plot. But the real trick to successful turf laying is in the preparation of the ground beforehand. There is a useful book you may be able to borrow from the library, or find on Ebay or Amazon (about a tenner new) called The Lawn Expert by D. G. Hessayon - its worth every penny, not only telling you how to lay the turf, but also how to prepare, and then maintain your grass.