A vs. An Indefinite Articles in English - Basic English Grammar

In this video, Alisha answers 4 questions. - When do we use the preposition TO in a sentence? In these examples, why do we use TO? - What is the meaning of "educated guesses"? - What's the difference? For example: "He is AN or A(a) European person." "This is A or UH one-way street" - I often hear two different pronunciations of the word "Neither", and today I'd like to know which one is right for me please.