When speaking about yourself, use je:
je vais faire des courses - I’m going shopping
When speaking to a friend, young person or family member, use tu:
tu aimes écouter de la musique - you like listening to music
Instead of a masculine noun, use il:
il était courageux ! - he was brave!
Instead of a feminine noun, use elle:
elle est partie en vacances - she went on holiday
When speaking about people in general, use on:
on s’est bien amusé - we enjoyed ourselves
When speaking about a group of people including yourself, use nous:
nous allons faire du camping - we’re going camping
When speaking to more than one person, an adult you don't know or a stranger, use vous:
vous voudriez visiter le château ? - would you like to visit the castle?
For more than one male, a mixed group or a masculine noun in the plural form, use ils:
ils iront aux États-Unis - they will go to the USA
For more than one female or a feminine noun in the plural form, use elles:
elles sont si intelligentes - they are so intelligent