Laying rustic loose paving slabs to make a path : don't need to bed them in mortar. Start by laying the slabs in place, to get the spacing and arrangement right. Dig out an area of soil, tamp it down well and make sure it’s clear of vegetation. Then add a 25mm bed of sharp sand. Smooth the sand and check that it's level, then lay the slab on top - taking care that the surface doesn't protrude above the level of the surrounding turf. Fill any gaps around the slab with soil or sand.
If you don't want to go to the expense of buying moulds, you can make your own moulds using a variety of methods. Marine plywood allows you to make larger moulds for laying decorative slabs or flooring for a patio. - See more at: http://www.home-dzine.co.za/garden/garden-diy-paving.html#sthash.3ASUE699.dpuf