Well the basics are easy Whisky (or Whiskey) is a distilled spirit made from fermented grain mash. It contains only 3 ingredients Grain (or barley), Water and Yeast.
The 2 main types of Scotch Whisky are Malt (made from Malted Barley) and Grain (made from Grain) whisky. In Scotland the spirit is generally distilled twice, with the exception of Auchentoshan which is triple distilled, and then stored in oak barrels to mature.
To be called Scotch Whisky the spirit must be distilled and matured in Scotland and must have been matured for a period of no less than 3 years and must be bottled at a strength of no less than 40% alcohol by volume (ABV)
This is just the basic information, more information will be added here shortly.