Summarize this article:

For each cutting you plan to make, select a small branch attached to the outside base of the lavender plant. A young, bendable branch is required, or a branch growing horizontal just above the soil surface. There are several related methods of propagation referred to as "layering." This one is simple and low-risk, but can be labor-intensive if you plan to create more than a few cuttings. Refer to the tips below if you want to turn your lavender plant into dozens of new cuttings instead. Dig a 4–6 inch (10–15 cm) hole in the soil, a short distance from the mother plant. Position this hole so you can bend the middle of the selected branch down into it, with the leaves and flowers at the end above ground on the other side of the hole. Hold the branch in place with rocks or a bent stake to prevent it springing out of the hole. Bury the center of the branch in soil to fill the hole, leaving the flowering end above ground. Water the buried section occasionally, keeping it moist but not soggy. Take care not to let the soil dry out during hot summer months.  Watering is not recommended while the plant is dormant for the winter. Mulch can help the soil retain water, but may cause plants to overheat during hot weather. While you can begin this process any time, the branch may not develop a strong stem and roots until the growing season in spring and summer. After three or four months of growth, preferably as cool autumn weather begins, carefully dig around the buried branch to look for roots. If they are present and clumping the soil together, cut off the branch so all the roots are on the same piece as the flowering end. Move the cutting directly to its new location, moving the surrounding soil along with it to avoid damaging the roots. Keep the plant sheltered from wind until stronger roots develop, and care for it as you would any lavender plant.

Summary:
Choose a small, young branch near the base of the lavender. Bury the middle of the branch in a shallow hole. Anchor the branch in place. Keep the buried branch moist. Dig up and cut the branch after at least three months of growing season. Transplant the cutting as a new lavender plant.