Measure the length and width of the area for which you are building a countertop. When you glue together the pine panels, make them an inch or two wider than the finished dimensions in both width and length and then cut them to a perfect finished size.
Joint the bottom faces of the pine boards by running them over the jointer. The purpose of a jointer is to smooth the bottom of a board enough that it runs flat when you feed it through the planer.
Plane the boards to create a flat and smooth top surface. Turn the boards over and plane the bottom surface until it is flat and smooth.
Run the edges of the boards across the jointer to make them smooth, straight and at a perfect right angle to the faces of the boards.
Lay a row of bar clamps on a flat workbench.
Lay the boards on top of the row of bar clamps. Stand all of the boards except for the last one on their edges. Cover the upper edges with glue. Lay the boards back down flat and press all of the boards together. Adjust the jaws of the bar clamps so they are pressing against the edges of the two outer boards.
Lay another row of bar clamps on top of the boards and position their jaws so they are gripping the edges of the outer boards. Tighten all of the bar clamps until glue begins to squeeze out from the joints. Leave the panel to dry for at least two hours.
Remove all of the bar clamps and scrape off excess glue with a paint scraper. Hand plane the surfaces of the panel to clean away glue and irregularities.
Cut the countertop to its final dimensions on a table saw.