。
I got two tickets from a friend.
Literal
Friend [from-から] tickets [subject-が] two-flat-things hand [into-に] entered [explanatory-んだ].
手に入る ('to enter one's hand') is an idiom for obtaining or acquiring something, with the thing acquired as the subject (marked by が). The counter 枚 is for flat objects like tickets. んだ (contracted のだ) signals that the speaker is sharing news.