Na-Adjectives

add Na-Adjective right before a noun but “Na” should be added between the Na-Adjective and the noun.

E.g.

すきな人

Suki na hito (favorite person)

あの先生は、わたしのすきな人です。

Ano sensee wa watashi no suki na hito desu. (That teacher is my favorite person.)

Just add Na-Adjective right before –desu

E.g.

ゆうめいです。

Yuumee desu. (It is) famous.

Just add “de wa arimasen” or “de wa nai desu.” 
"De wa" is casually pronounced as "jaa" in spoken language. (the "Wa" is the particle so it is written with "は(not わ)."

Note: Remember how to say “(I) do not like (something)?   

(something) wa suki jaa arimasen. 

E.g.

ゆうめいではありません。

ゆうめいではないです。  (It is) not famous.