They
pronoun, の adjective
This is he but plural. The "ra" makes it plural, making it "they" or "them." While this gennnnnnerally refers to a group of males, it can include ladies too.
かれら
The reading is the same as the one you learned with the kanji.
彼らはみんな、電車の切符を買っていなかったため、無賃乗車者として捕まった。
None of them bought train tickets and they were caught for riding without paying.