To communicate your orders, instructions and wishes in German, you use the imperative form of a verb.
If you want to look up this phenomenon in a German grammar, please look for ‚Imperativ‘ or ‚Befehlsform'.

• In the singular you address one person: the ending of the verb is deleted and the personal pronoun is omitted.
  Example:
  Du gehst in das Haus. → Geh in das Haus!
  You (sg) enter the house. → Enter the house.
• In the plural, you address several persons: the personal pronoun is (again) omitted and the ending of the verb just stays the same.
  Example:
  Ihr geht in das Haus. → Geht in das Haus!
  You (pl) enter the house. → Enter the house!