Oracle-bone 年 drew a person carrying ripe grain home on their back. One harvest equaled one year — time was measured in what you could carry from the fields.
新年 is New Year, 过年 is celebrating it, and the 年 was also a legendary monster scared off each spring with red paper and firecrackers — which is why Chinese New Year is loud and scarlet. 今年、去年、明年: this year, last year (the 'gone' year), next year (the 'bright' year).
A farmer hauling the harvest home — one load of grain, one YEAR.
年年有鱼 'fish every year' puns on 年年有余 'surplus every year' — the reason a whole fish appears at every New Year dinner and is deliberately never finished.