The first step in creating a rock garden is to sketch at least sufficiently detail, show the outline, show the path, and so on.
These points are best characterized by fairly strong bets that are pushed to the ground or likely to be cleared. If you want to buy garden edging products then you can pop over to this site.
If there are no ledges or rocks, some digging is needed to get started. It's not just for drainage. If a rock garden is laid out only on the ground level, then at this point there will be disturbances, which will greatly affect the moisture supply.
The foundation or foundation of the rock garden structure must be completely buried in the ground. The basis should be mostly of rock and whatever sculpture in the yard remains for later. Here small fragments, flat stone, soft stone or slate, any shard of rock unsuitable for use above ground, can be used for "filling" purposes.
Old brick or stone scraps will answer; Slag (not soft ash) works fine. The largest rocky foundation, the top of which appears above the ground, must be deep underground. Incidentally, excavation provides soil for use above ground.
Under normal conditions, when soil drainage is good, 12 or 15 inches is sufficient for this initial excavation; often less on slopes or on land. If the ground is hard, it must be well crushed with a pickaxe. Many authors recommend digging three or four feet. It's much easier to recommend than to meet – you're more likely to meet the recommender. Such depth is only needed if drainage is abnormally poor.