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 do at the beginning of the sentence?
(This sentence is from a text about 春节)
Here the use of 和 and 差不多 is similar to the phrasing "Like how" in English.
"Like how Westerners celebrate Christmas, this [Chinese New Year] is a holiday when the entire family gets together."
A literal meaning of 和 is "with." But here, the context is not a literal with. It's more like "similar to." That could be "with" in a figurative sense.
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