N5
くて・で（並列）
くて・で（へいれつ）
And... (Conjunctive)
音楽を作るのは仕事で趣味だ。
Making music is both work, and my hobby.
Explanation
The て-form of adjectives and nouns links several descriptions into one sentence:
1い-adjective: drop 「い」 and add 「くて」: 「安くておいしい」 (cheap and tasty).
2な-adjective: use 「で」: 「静かできれいだ」 (quiet and pretty).
3Noun: use 「で」: 「日本人で学生です」 (is Japanese and a student).
This lets several short sentences become one.
Mixed up with
The descriptions joined this way usually point the same way: all good, 「新しくて便利」; all bad, 「狭くて暗い」. If one is good and one bad, use 「が」 or 「けど」: 「古いですが、きれいです」 (It's old, but clean).
The て-form of 「いい」 is 「よくて」, never 「いくて」.
It can also carry a slight sense of cause: 「頭が痛くて寝ていた」 (I had a headache, so I was sleeping).