I know how to use 和 to link one or more nouns or noun phrases, but in this sentence I don't understand what purpose does it serve at the beginning of the sentence?
(This sentence is from a text about 春节)
The best way to translate the 和 in this sentence is using "how".
The sentence roughly translates to "Spring festival is similar to how Westerners spend Christmas, this is a festival where the whole family gets together."
However, this is more of a contextual translation. 和 should be closer to "with" but it doesn't make exact sense to say Spring festival is similar to being with Westerners at Christmas...
Normally you would see something like this:
Eating with Westerners
Spend Christmas with Westerners
"和" here means "and".
The subject is omitted. Usually it is "This", "I", "We", "My something" or "Our something".
is the same as
For simplicity, you can understand this way.
(The way of) Our festival and Westerners' Christmas are pretty much the same.
The omission is pretty common in Chinese languages like Mandarin, Cantonese, Classical Chinese. The omission part is mentioned before or can be understood by context.
Classical Chinese : "與你何干？" and "與你把臂同遊。"
Cantonese : "同你食飯"