Summary: sentence brackets (Satzklammer)

If there is more than one verb or parts of verbs in a clause, the following rules apply:

• A verb or part of the verb is in the second position and is conjugated.
• The other verbs or parts of verbs are at the end of the sentence. Their form is not adapted to the subject but remains the same.

Examples for this sentence structure are clauses and sentences with modal verbs, sentences with separable verbs and sentences in the perfect tense.

Sentences with modal verbs: 

Du sollst dein Zimmer aufräumen.
Nico soll sein Zimmer aufräumen.

Sentences with separable verbs:

Ich räume mein Zimmer auf.
Nico räumt sein Zimmer auf.

Sentences in the perfect tense:

Ich habe mein Zimmer aufgeräumt.
Nico hat sein Zimmer aufgeräumt.