End Game Review

Hello, I am wondering how the massive end game capture came about in this game (https://online-go.com/game/4417548). Did I play the right moves throughout the game or was it more of a case of beginners luck or was it the case where my opponent made mistakes? Thanks all for the replies. Please let me know what mistakes I made in this game so I know what not to do next time.

I’m a humble double-digit kyu, but:

White’s move 48 at H2 saves the group. But white’s groups on the left are still weak, so this looks like a convincing win for black.