Mark the outline of the sidewalk with stakes and builders twine. Make sure outside lines are straight unless it is a curved sidewalk. Use a tape measure to keep the width exact. Excavate the area inside the lines with a shovel 8 inches deep if using 2-inch thick pavers, which is the standard depth of concrete pavers and bricks. Lay black plastic or landscape fabric over the dirt to prevent weeds from infiltrating.
Install some type of restraint on the edges of the walk. Use steel, plastic or similar edging to make a barrier for the sidewalk underlayment. Lay medium gravel 4 inches thick over the entire area and compact it with a hand tamper or a mechanical device if it is a very long sidewalk. Spread 2 inches of sand on top of the gravel and smooth it with a board across the width of the walk.
Start at one end laying pavers. Set the first one in place, square with the edge and use a level to get it level. Add the second paver alongside, then work down and across the sidewalk placing pavers. Check every paver with a level to keep the walkway level both across the width and down the length. Set pavers in any desired pattern. Offset seams or use a criss-cross pattern, whatever fits your design and paver style.
Place pavers the length of the walk. Use a hand tamper to set all pavers firmly into the sand, checking with a level to keep the surface level. Sweep polymeric sand, which will become firm when dampened, into the seams between pavers with a broom. Fill any joints completely with sand. Use a garden hose with a misting nozzle to wash excess sand off and solidify sand in the seams..