First, I place my plants, still in their nursery pots, into my container to get a general idea of the container design and where I want them to go. I move the plants around, still in their pots, until I'm satisfied with the arrangement. I do this while they are still in their pots to protect the fragile root systems. I then take all of the plants out of their pots and place the plants in the container.
Once you are satisfied with the way your arrangement looks, you’ll then want to take your succulent potting soil and pack it gently around and in between your plants. As you do this, be careful to keep the soil at the level the plant was in its nursery pot. You don’t want the new soil to touch the crown (the part of the plant that meets the soil) of your succulent plant.
Make certain that you have filled in all the holes and spaces, between the plants and also between the plants and the sides of the container. If you don’t, the roots will dry out, which can be lethal to your succulent plant.