Wood planking, whether for a ceiling or wall, generally comes in tongue-and-groove systems that lock together at the sides. They have to be secured to ceiling joists or wall studs. A finishing nail gun (not a framing gun) is used to face-nail the first plank in place. Subsequent planks are nailed through the sides so the nail heads are hidden. It's important to leave gaps at the edges of the planked area to allow the wood to expand with climate changes. The gaps are hidden by trim.
Mark out the ceiling joists or wall studs, using an electronic stud finder, level and pencil.
Measure along one edge of the ceiling perpendicular to the joists, or along the bottom of the wall. Cut a plank to that measurement, using your mitre saw.
Hold the board to the ceiling or wall with the grooved side of the plank facing the adjacent wall or the floor. Leave 1/2 inch of space there.
Shoot nails through the face of the plank at each place where it crosses a joist or stud, using the finishing nail gun. Shoot the nails in pairs at each point.
Measure and cut the next plank. Set it against the first one, pressing them together to get the tongue-and-groove sides to connect. At each point where the second board crosses a joist or stud, shoot a nail through the side of the board at a 45-degree angle, just above the tongue.
Repeat the process for each of the boards, cutting them to length, fitting them together and nailing them through the sides. Do the whole space.
Cut the last plank along its length on a table saw, so it will fit against the wall with a 1/2-inch gap there. Shoot nails through the face of the plank to secure it, as with the first plank.
Install trim along the edges of the planking, cutting it on your mitre saw and securing it with your nail gun, to hide the gaps.
Wear goggles when cutting and hanging the planks.