YOU SAID:

Id go tomorrow but i have to help my underclassmen with a chinese event on friday

INTO JAPANESE

明日は行くけど、金曜日は中国のイベントで後輩の手伝いをしなければならない

BACK INTO ENGLISH

I'm going tomorrow, but on Friday I have to help my juniors at an event in China.

INTO JAPANESE

明日行くのですが、金曜日は中国のイベントで後輩の手伝いをしなければなりません。

BACK INTO ENGLISH

I'm leaving tomorrow, but on Friday I have to help my juniors at an event in China.

INTO JAPANESE

明日出発するのですが、金曜日は中国でのイベントで後輩の手伝いをしなければなりません。

BACK INTO ENGLISH

I'm leaving tomorrow, but on Friday I have to help my juniors at an event in China.