Excavating the Space

Excavate the installation area. Spaces which will be exposed only to foot traffic generally need 4-6" of base material, while driveways or projects in very wet soil may need as much as 12" of base. Figure out how deep your base will need to be (consult Silt Tool Rental), and add about 1-1.5" for the sand layer, plus the thickness of the pavers (this varies by brand and style but is typically 2 3/8" or 3 1/8"). The sum of the depth of the base, the sand, and the pavers will be how deep you need to excavate your project area. Be sure to excavate 6-12" beyond the boundaries of the project to give you ample space to install your edge restraints.
Measure the depth of your excavation from the string you used to track your slope, not from the surface of the ground.
Measure the depth of your excavation from the string you used to track your slope, not from the surface of the ground.

Choose your base material. Base material is usually coarse, crushed stone with sharp irregular edges. The two most important things about base material is that it remains strong when compacted (to serve as a base for your pavers) and that it drains properly. Poor structural integrity and poor drainage can ruin an otherwise perfect paving project.

Lay the base. Add no more than 6 inches (15.2 cm) at a time to the entire excavated area, and then compact with a hand tamper (for very small projects) or a mechanical plate compactor. It's essential that the base be well-compacted. Repeat this process until you have a base of the correct depth. Now is your last chance to properly adjust the height of the finished project and to ensure you don't have any dips or bumps. Slightly increase or decrease the thickness of the base as necessary, taking frequent measurements from your strings to the base.
Be sure to lay base material beyond the planned boundaries of the pavers. Laying the base outside the boundaries of the pavers will make your project more stable.
Continue adding base material and then compacting every 2 inches (5.1 cm) until you are about 3 inches (7.6 cm) from your desired finish height. When compacting, be sure to maintain a gentle slope — usually away from your house.
Be sure to lay base material beyond the planned boundaries of the pavers. Laying the base outside the boundaries of the pavers will make your project more stable.
Continue adding base material and then compacting every 2 inches (5.1 cm) until you are about 3 inches (7.6 cm) from your desired finish height. When compacting, be sure to maintain a gentle slope — usually away from your house.
Install the edge restraints. Edge restraints will help hold the shape of your project over the years. Place these restraints, usually made of plastic, aluminum, or steel, around the perimeter of the project and secure them into the ground with 12" spikes. If your design is irregularly shaped, you'll need to cut the restraints in order to follow the edges of your design.

Put down a layer of sand. The sand is the material that holds your pavers in place. Use coarse sand and screed it smooth to a uniform depth of at least 1 inch (2.5 cm), but no more that 1 1/2 inches (5.1 cm). If your project is large, lay down 1" screed pipes and then pour the sand in between the pipes, screeding the sand in small sections (50-100 square feet each). Remove the pipes and then fill in the gaps with more sand.