Learn French: Nous attendons une équipe créative et sérieuse. - We are waiting for a creative and serious team.

Because it describes une équipe, which is a feminine noun. Adjectives ending in -f in the masculine (like créatif) change to -ve in the feminine (créative).

Why does the sentence use sérieuse instead of sérieux?

Just like with créative, this adjective has to match the feminine noun équipe. Masculine adjectives ending in -eux (like sérieux) change their ending to -euse when they become feminine.

Where is the word for "for" in this sentence?

The English translation says "waiting for", but the French verb attendre inherently means "to wait for". You never add an extra preposition like pour after it.

Why do both adjectives come after équipe?

In French, most adjectives go after the noun they describe. Only a specific group of short, common adjectives (often remembered by the acronym BAGS for Beauty, Age, Goodness, and Size) go before the noun. Since these two don't fit that rule, they follow the noun.