When do you use 'a la' and when do you use 'au'? How do you know which one to use?

[Using the whiteboard and colours to differentiate the feminine, masculine, and plural]. 'A la' and 'au' are linked to the genre of the subject of the sentence. The subject is what you are talking about. For example:Je vais à la plage --> we say 'à la' because 'plage' is feminine (La plage) Je vais au zoo --> Zoo is masculine and we cannot say 'à le', so we replace it was au instead. It also important to remember that if the subject is plural, then we use 'aux' instead of 'à les'. For example: Je vais aux Etats-UnisUnfortunately it means that you have to learn about the genre of the noun- there is no particular rule for that, it is something you have to learn (a good habit to take up when learning new vocabulary is to learn the genre at the same time).Let's practice with a few together.