に座る

sit in / sit on / sit at

→ に
phrase Very common #596
sit in / sit on / sit at に marks the place, seat, or surface where someone sits. The exact English preposition depends on the location: for example, 椅子に座る means “sit on a chair,” while 席に座る means “sit in a seat.”
JA: 私は窓の近くの席に座るのが好きです。
EN: I like to sit in a seat near the window.

最初は俺が助手席に座る

I'll sit in the passenger seat first.

— ビッグ・シック ぼくたちの大いなる目ざめ (2017)

その上に座るな。

Don't sit on it.

このいすに座ると、すっかり気分が落ち着く。

Sitting in this chair completely relaxes me.

俺たちはこっちに座る

We'll sit over here.

— 道 (1954)

その上に座るな

Don't sit on it.

— ラ・ラ・ランド (2016)