Create a base with borders. You can do this by digging down into the ground where you want your path and use the edges of your trench as the border, or you can design a path and line the sides with decorative rocks. Rock borders are somewhat difficult because you must hand pack the asphalt in between the rocks with a tamper. Aesthetically, though, rock borders are preferable. Either way, you want at least a 2- or 3-inch drop from the top of the border to the base of the path. Otherwise, the walking path will be above the terrain around it rather than being a part of it.
Prepare the base of the walk. Remove any big rocks from the eventual path with a pick. Rake the base flat and shovel any loose dirt out of the path. Run the roller packer over the path to compact the ground. If necessary, spray the path with a light amount of water if you are having trouble compacting with your roller. Dirt must have a small amount of water in it to compact sufficiently.
Wheelbarrow the asphalt over to the path and drop it. Fill the entire path of your walk with asphalt. The walk should be 2- to 3-inches deep prior to rolling. First rake the asphalt flat, then rake asphalt from the edges to the center. You want a slight angle from the center-line of the walk down to the edges. This is called crowning. Crowning is necessary to prevent puddles in the middle of the walk after it rains or after you water your lawn.
Run the roller packer over the walk. Begin on one side (left or right) of the walk, then move to the other. Last, roll the center of your walk. This will assure that you maintain the crown of the walk. Make as many passes over the walk as you have patience to make. Generally speaking, five or six passes will suffice, but the more you roll the walk with the compacter, the more durable your walk. If you use a rock border, be sure to hand compact between the rocks with the tamper.