How can you say .... in Japanese
Please i need somebody to help to translate some simple phrases to japanese

Excuse me, is that sit idle?

I eat a delicous lunch today.

My mother told me to not do that thing.

You are very helpful, thank you.

Question

How can you say .... in Japanese
Please i need somebody to help to translate some simple phrases to japanese

Excuse me, is that sit idle?

I eat a delicous lunch today.

My mother told me to not do that thing.

You are very helpful, thank you.

Answer

Hi, Daniel.C!

Excuse me, is that sit idle?
→If you mean, "is that seat idle (is that seat open)", it is as follows.

Excuse me,
=Sumimasen,
＝すみません

is that sit idle?
=Sono seki wa aite imasuka？
＝その席（せき）は空（あ）いていますか？

I eat a delicous lunch today.
→If you mean, "I ate (in the past tense) a delicious lunch today" it is as follow. 
=kyou no hiru gohan wa oishikatta desu.
=今日（きょう）の昼（ひる）ご飯（はん）はおいしかったです。

My mother told me to not do that thing.
＝haha ni, souiu koto wo shinaiyoni iwarete imasu. 
=母（はは）に、そういうことをしないように言（い）われています。

I hope this helps, Daniel. 
If you have any question, write to me!

Answer

Yes, i forgot to write in the past tense the verb eat, sorry, and by iddle i mean unoccupied.
Thank you very much Ms Madoka.