Great question, okay directions can refer to the way of describing how to get from a to b, such as driving directions, take a right here a left here, etc... Directions can also refer to cardinal directions such as north, south east west. Directions can also be a synonym for instructions meaning the step by step guide to doing something, such as the directions (or instructions) to put together a piece of furniture, or how to play a board game.

Both, directions and instruction act as guidelines. It depends on the context. Instructions are mainly associated with teaching.