YOU SAID:

I have a tennis lesson today at one o'clock.

INTO JAPANESE

今日は1時にテニスレッスンを受けます。

BACK INTO ENGLISH

I will have a tennis lesson at 1 o'clock today.

INTO JAPANESE

今日は１時にテニスレッスンをします。

BACK INTO ENGLISH

I will play tennis at 1 o'clock today.

INTO JAPANESE

今日は１時にテニスをします。

BACK INTO ENGLISH

I play tennis at one today.

INTO JAPANESE

今日はテニスをします。

BACK INTO ENGLISH

I play tennis today.

INTO JAPANESE

今日はテニスをします。

BACK INTO ENGLISH

I play tennis today.