A1
と — and, with, together
How と links nouns and marks the person you do something with in Japanese, and why it never joins clauses the way English “and” does.
と joins nouns into a list, and marks the person you do something with.
パンと卵を買います。
Pan to tamago o kaimasu.
I’ll buy bread and eggs.
友達と行きます。
Tomodachi to ikimasu.
I’ll go with a friend.
Both readings come from the same idea — two things taken together — and context separates them without difficulty.
An exhaustive list
と implies the list is complete. や is the particle for and others, among them, which is a distinction English makes with and so on if it makes it at all.
本や雑誌を読みます。
Hon ya zasshi o yomimasu.
I read books, magazines and so on.
It does not join sentences
This is the mistake to avoid. English and connects anything; と connects nouns only.
朝ご飯を食べますと学校に行きます。
朝ご飯を食べて、学校に行きます。
Two actions need the て form, not と. と can only ever sit between nouns. See the て form.
Quoting
A second job worth recognising early: と marks reported speech and thought, attaching to the whole quoted piece.
明日行くと言いました。
Ashita iku to iimashita.
He said he’s going tomorrow.
The quote comes first and the verb of speaking comes last, which is the same verb-final order as everything else in the language.