Obtain Adirondack chair plans. Plans for the Adirondack chair are found online for free or in woodworking books.
Transfer the patterns to the pine boards using the marking pen. Some plans are full-size while others come in small sizes and need to be expanded prior to transfer.
Place the marked pine boards on the workbench. Use the jigsaw to cut the pine boards along the scribed marks.
Select the leg, arm and back frame pieces. Attach the arms to the back frame with the cordless drill and wood screws. First drill pilot holes with a 1/8-inch drill bit. Then replace the drill bit with a screwdriver bit and drive screws in the arms according to the plans. Use the cordless drill, drill bits, screwdriver bits and wood screws to attach the legs to the arms. There will now be a frame of a chair, with arms attached, ready to accept the seat slats and back slats.
Attach each of the seat slats to the leg frame using the cordless drill and wood screws. First, drill pilot holes in the slats with a 1/8-inch drill bit. Then replace the drill bit with a screwdriver bit and drive screws in the slats according to the plans. Attach the back slats to the back frame in the same manner. Use the cordless drill and wood screws to attach any additional decorative pieces.
Use the sandpaper to sand the entire chair until smooth. Take special care to sand the outer edges of the armrests and the seat slats as these come in direct human contact.
Use the paintbrush to apply either paint or varnish. Apply one coat and then wait one day to apply another coat.
Put the chair on a level surface and test to see that the seat legs rest firm and do not wobble. If the legs are not firm, use the jigsaw and sandpaper to make any adjustments necessary.