Here are some ways "and" is used:
* Connecting nouns: "I bought apples and oranges."
* Connecting adjectives: "The house is big and beautiful."
* Connecting verbs: "She sings and dances."
* Connecting phrases: "He walked quickly and confidently."
* Connecting clauses: "I went to the store, and I bought some milk."
* Connecting sentences: "It was a sunny day. And the birds were singing."
In essence, "and" signifies a joining or combining of two or more things. It adds to or expands upon what has already been said.