I found this video at Youtube which give a really quick indication as to how to lay paving slabs, and also how to cut a paving slab in half using a hammer and chisel.
The video says that slabs should be laid over a bed of sharp sand and a 1:5 mortar mix should be used to anchor the paving, particularly when heavy items (lawnmowers, patio furniture) will be moved across the finished paving. The mortar dabs are placed at each corner, and one in the middle, then the sides of the paving slab are buttered with mortar before the slab is laid and gently hammered into place using the shaft of the hammer. A spirit level is used the check that the slab is horizontally level. It’s easier to butter the sides of the slabs when laying them than trying to fill the gaps between them afterwards, and it avoids the possibility of mortar staining the slabs.