With any paving project, the two most critical factors are compaction and drainage. Make sure that there is at least 1" of slope to every 4' of run, away from any buildings etc. and preferably in the general direction of the surrounding terrain to avoid puddles from forming.
If there is not going to be vehicles on it, a 5" base of packed limestone screenings will suffice for a base. Mark out your area and dig down 8" and as much as possible, don't disturb the ground below the 8" level. Level the dug out area as much as possible and compact it with a rented plate tamper. Shovel and rake in 3" of limestone screenings, level and compact with tamper again. Shovel in and rake the remaining 2" of screenings, but this time you will want to grade in your slope with a rake. Tamp again, rake out/in any high/low spots and tamp a final time. You are now ready to add your paving stones.
Simple, huh?
OK, I really abreviated this in the interests of saving time, but you can get the basic idea from this and you can ask any question at any time, glad to help.
