YOU SAID:

I'm only halfway up the stairs, not up or down.

INTO JAPANESE

私はない上下、階段の途中までのみです。

BACK INTO ENGLISH

I am only partway, not up and down the stairs.

INTO JAPANESE

わからないだけ途中、階段の昇り降り。

BACK INTO ENGLISH

Just do not know on the way up and down the stairs.

INTO JAPANESE

途中で階段の昇り降りを知らないだけ。

BACK INTO ENGLISH

Just do not know the down stairs in the middle.

INTO JAPANESE

途中で階段を知らないだけ。

BACK INTO ENGLISH

Just do not know the stairs in the middle.

INTO JAPANESE

途中で階段を知らないだけ。

BACK INTO ENGLISH

Just do not know the stairs in the middle.