A simple explanation

Word	Basic use	Examples
get	We normally use get with adjectives in everyday spoken English. It often describes a gradual or temporary change.	get tired get hungry get cold get lost
become	We use become before nouns when something or someone changes into a new role, position or type of thing.	become a guide become friends become a problem become a tourist attraction

Get + adjective:
It is getting hot.
We got tired.
He got lost.

Become + noun:
She became a tour guide.
The castle became a tourist attraction.
They became good friends.

With many adjectives, both verbs are grammatically possible. However, get usually sounds more natural in everyday conversation, while become sounds more formal.

Kurz erklärt:
Get wird in der gesprochenen Alltagssprache normalerweise mit Adjektiven verwendet: get tired, get hungry, get cold. Become wird vor einem Substantiv verwendet, wenn jemand oder etwas eine neue Rolle, Funktion oder Form annimmt: become a guide, become friends, become a problem.