Wooden Stairs allow you to get to a higher block level without having to jump. They are generaly used in paths that need to go up more than one block level. Steps are used in paths that only need to go up one level.
Recipes to obtain Oak Stairs
Recipes that require Oak Stairs
Oak Stairs can not be used for crafting.
Recipes to smelt Oak Stairs
Oak Stairs can not be smelted.
Recipes that require Oak Stairs to smelt
Oak Stairs can not be used for smelting.