YOU SAID:

i was sitting in my chair and then

INTO JAPANESE

私は私の椅子に座っていたし、

BACK INTO ENGLISH

I sat in my chair, and

INTO JAPANESE

私は私の椅子に座って、

BACK INTO ENGLISH

I sat in my chair,

INTO JAPANESE

私は私の椅子に座ってください。

BACK INTO ENGLISH

I sit in my chair.

INTO JAPANESE

私の椅子に座る。

BACK INTO ENGLISH

I sit down in my chair.

INTO JAPANESE

私の椅子に座る。

BACK INTO ENGLISH

I sit down in my chair.