Unwind 1/2-inch tubing and place it along the primary area you wish to water. If this area is a distance from your hose bib, allow enough length to bury the tubing between the hose bib or spigot and the garden area where you need water. Use the stakes for 1/2-inch tubing to hold the tubing in place. Allow the sun to warm and relax the coils of tubing for a while, especially if working in cool weather. Bury 1/2-inch tubing as needed when final location is established.
Attach the hose Y or multi-valve outlet you have selected directly to the hose bib or spigot.
Connect the pressure reducer to the hose connector. Connect the 1/2-inch tubing to the adapter and then connect the adapter to the pressure reducer. Connect this end to the hose Y or multi-valve adapter. Open the valve that provides water to this tubing. Leave the water off for now.
Determine where you need Ts or Ls in the half-inch tubing. Cut the tubing where you need to add fittings and attach. Some fittings may have screw-tight pressure fittings. Other fittings may need the tubing to be worked into the end. Check that connections are secure.
Close the far end of the half-inch tubing with the tube end -- sometimes called a figure-eight crimp -- by placing it on the tube, folding the tube and placing the folded end into the other side of the closer. This crimps the end of the tubing closed. Turn on water and check for leaks. Turn the water off. Release closure and re-close as needed to relieve water pressure while you continue to work. Check that the washers are in place on all threaded connections that leak. Plumber's tape may be needed if you have leaks on threaded pieces with washers in place. Wrap threads with one or two layers of silicone thread tape and reconnect.
Lay out 1/4-inch tubing from half-inch tubing to plant. Cut 1/4-inch tubing and attach barb connector to one end. Punch hole in 1/2-inch tubing and connect the 1/4-inch barb by inserting it in the punched hole. If you accidentally punch a hole in the wrong area of the tubing, place a "good plug" in the hole. Connect Ts and Ys to 1/4-inch tubing as needed. Attach sprinkler to end next to plant. Use a 1/4-inch tube stake to hold sprinkler in place.
When all sprinklers are in place, re-close the 1/2-inch tubing. Turn water on and adjust sprinklers to the desired amount of water for each plant.