Use a stud finder to find and mark all the joists in the ceiling. Draw lines over the whole ceiling showing the course of each of the joists.
Measure the length of the ceiling at the side where you want to start, which must be perpendicular to the joists.
Transfer the measurement to a ceiling plank. Cut it straight across (at 90 degrees) with a miter saw.
Set the board up to the ceiling, with the grooved side facing the wall and sitting half an inch out from it.
Nail the board in place with a trim nailer, driving nails through the face and into the joists above it. Use two nails per joist.
Use a miter saw to cut the next board to size. Set the grooved side of the new board to the tongue side of the previously hung board. Secure the new board by shooting nails at an inward angle through the side rather than the face
Repeat the process to hang each board, crossing the ceiling course by course.
Cut the last board lengthwise to fit against the far wall, using a table saw and leaving a half-inch gap. Ceiling trim will hide the gaps.