The Imperative Mood

The imperative mood is used for commands and instructions. It can only occur in the second person, so we just need to learn three main forms: du (informal singular), ihr (informal plural), and Sie (formal singular & plural). The du form is just the present tense du form without the st ending:
geben to give --> du gibst 2nd person singular --> Gib mir das! Give me that!
nehmen to take --> du nimmst 2nd person singular --> Nimm die Schlüssel mit. Take the keys with you.
The ihr form is identical to the present tense:


Finally, the Sie form is also the same as the present tense, but the Sie is included after the verb. There can be a slight tension between the respectful tone of Sie and the fact that you’re giving an order, so this is often softened with bitte (please) – and in practice it’s used mainly for polite requests, not outright commands.

Nehmen Sie bitte eine Broschüre. Please take a brochure.

The verb sein is irregular in the imperative, based on the infinitive instead of the conjugated stems:
"du" form: Sei still! Be quiet! "ihr" form: Seid brav, Kinder. Be good, kids. "Sie" form: Seien Sie bitte geduldig... Please be patient...
That's it for the conjugated imperative forms, but there are two related forms you should be aware of. The first is the "infinitive imperative," which is common in posted rules and regulations. When it's used in speech, it usually has a sharper "drill sergeant" tone than the forms above. You probably won't use the infinitive this way yourself, but you should be able to recognize it. Unlike "true" imperative statements where the verb comes at the beginning (as in all the examples above), when you use the infinitive this way it comes at the end:

Hinten Anstellen! Go to the back! [of a line]

Nicht mit dem Fahrer sprechen! Don't speak to the driver!

And finally, there's a "friendly suggestion" formation in German that's equivalent to "Let's..." in English. It's the same as the normal "wir" present tense form, you just switch the order of the verb and pronoun:

Lass uns zur Seitentür reingehen. Let's go in the side door.