Transferring force
Axles and gear boxes are needed to transfer rotational force. Gear boxes have an input side marked with arrows and a hole, all other sides are outputs. Gear boxes can be turned off with redstone which means that no force comes out of its outputs. Axles can be connected up to a length of 3, the 4th axle breaks when powered. Machines that require rotational force usually have clearly marked input sides as well.
Generating force
Rotational force can be generated using either a wind mill or a water wheel. The generator needs to be placed on an axle. Only 1 generator is needed per network. The wind mill needs a lot of space as a special requirement while the water wheel is smaller but requires a stream of water below. Wind mills can break during thunder if the gear box they are attached to is not turned off. A hand crank can be used to manually generate force but it only works for the mill stone. Hand cranks break when they power more than 1 mill stone.