| Hi Jeff, First comes the concept (the why), then the meaning and understanding of the space, then the direction and desire for the space and then the design.Design usually will take 6 months to two years. All calculations are eventually made (as to exactly how many rocks, where they go etc). Once the construction phase begins, mountain sides, collecting areas and rock quarries are visited, once a collection site is choosen each rock on the plan is seeked out (we will have desired demensions, weight and feeling for each rock). It begins by looking for the most important rocks, - bridges, waterfalls and the like. Usually for waterfalls the entire arrangement is mocked up at collection site to assure the final arrangement is perfect and then the rock is labeled and moved to the site for final placement. This process is followed for any high grade rockwork including facing for walls or ground surfaces, groupings and shorelines. They're laid out on the ground, then they are numbered and moved to the site and placed. Once the main rocks ( usually about 40% of what's needed) are found the rest (the in between rocks) are easily found. Of most importance is choosing the site to collect the rock, it is most desirable that all rock for a particular garden has the same history (that is that they all come from the same place). Once the correct rock is aquired the rest of the garden will easily fall into place.
There's an old Japanese saying:
To create a garden one must first have the space, a sponser and rock before considering to build. Gerald | 
