1. 'Another' is just the two words 'an' (indefinite article) - meaning 'one' -and 'other' (adjective) written together as one word. An (one) + other = another Do you know when to use the article 'a' or 'an'? Of course you do - that's easy. You use the indefinite article with singular countable indefinite nouns: an apple, a book, and so on. Well, using the adjective 'another' is exactly the same. An apple ---> 'an other apple' ----> another apple A book ----> 'an other book' ---> another book. 2. You use 'other' on its own with all other nouns - plural nouns ('books') and uncountable nouns (for example, 'information'). With these words, there is no article, so we just say 'other books' and 'other information'. We also use 'other' on its own after other determiners, for example 'My other book' or 'That other apple'. I hope that makes sense. I would be a multi-millionaire if I had a penny every time someone has asked that question. And the answer is so simple: an + other = another.

There is explanaton in the first part of this video: https://www.youtube.com/watch?v=lqtFCGkSTM4 I hope it helps)

The difference depends on what you're going to refer to, for example "the other day" and "I want to draw another drawing" if you need more help you can either contact me here or on Skype (henrik.rostad)