There are two ways of saying “you” in English, but there are four ways of saying it in German! The rules are pretty straight forward, so just relax. We’ll take you through these principles step by step.
Resources for further reading:

How to pronounce German Pronouns
One or more?
Below you can see the German pronouns in the singular form, as in when talking about a single person, and plural form, as used when talking about a group of people.
Just one (singular)
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Which “You” is You ?
You will notice that pronouns in the singular and plural forms (as described above) both have a “you”, (“*du” and “Sie” in German). Back in the days of Shakespeare, people used the words “thou” and “thee” to address their friends or loved ones (royals were addressed with the more formal “you” and “ye”). These polite forms of “you”* have fallen out of use in modern-day English, but German has maintained a distinction between familiar and polite forms of “you” which are used in the following ways:
The “sie” form of “you” is used in a global way when you are addressing several other people, not including yourself. “Sie “ also means “she”
The “Sie” form of “you” is also used when you wish to be polite or show respect to an individual or a group. You might use it with strangers, the elderly, teachers, or authority figures. In German, addressing someone with “Sie” always creates a respectful distance which can be very useful to emphasize a point. “Sie” is spelled with a capital “S” when used in a formal way.
The “du” form of “you” is used to speak to children, friends, family members, or loved ones in a casual, relaxed and familiar way
The “ihr” form of “you” is used when you are addressing several other people, not including yourself in a casual way, like “you guys”.
If you are in doubt, just use the polite form “Sie”. A relationship often begins with the more formal “Sie” and progresses to the more casual “du”.
In short:
Addressing people in a global or collective sense = sie
Addressing individuals or groups in a formal respectful way = Sie
Addressing someone in a casual sense = du
Addressing a group in a casual way = ihr
For example:

Brauchst du Hilfe?

Sie wollen Schuhe für Marie kaufen.

Ihr könnt draußen spielen.

Here are a few recommended German lessons to try next!
- Let's take a look at the German verb stems.
- There are eight standard German vowels. Let's take a look at them!
- Break the ice by talking about your hobbies in German.
Bis bald!
Paul Weber: Rocket German