When making a rock garden, you will quickly learn that if you are utilizing an existing slope in your garden, a lot of the work is already done. Dig out the section you want to transform into a rock garden and dig in some organic matter to help your plants settle in. If you are creating your space from scratch then dig out your chosen area and mound it up with earth, trying to incorporate a gentle slope, or mound - you may need to use additional bagged top soil or compost to create the shape.
It's a good idea to edge the border of your rock garden by using either large pebbles, bricks, or decorative wooden edging. This retains the rock garden, and defines the space, as well as looking decorative.
Place your rocks until you are happy with their position and dig out a little earth to let them settle - most of the rock should be visible though. Remember that odd numbers look best, and leave enough space between the rocks for planting.
Before removing your plants from their pots, put them in the places where you think they will look good and move them around until you are happy with how the rock garden looks. You can now plant one at a time, removing from the pots as you go. It is fine to plant them right next to the rocks as this is their natural habitat.