Understanding the 「内容」 meaning of the で particle


On page 21 of
「[初級を教える人のための日本語文法ハンドブック](https://www.amazon.co.jp/-/en/%E5%BA%B5-%E5%8A%9F%E9%9B%84/dp/4883191559/)」,
the authors make a valiant attempt at compiling the meanings of Japanese
particles. The chart is at the bottom of this post. However one has always
been difficult for me to comprehend, and that's the 「内容」 meaning of で.

(The asterisk after 内容 indicates that details are explained in [the book's
sequel](https://www.amazon.co.jp/-/en/%E5%BA%B5-%E5%8A%9F%E9%9B%84/dp/4883192016/),
but unless I'm somehow missing it, I can't find information about it there.)

Other than 「進学のこと **で** 先生に相談する」from the chart, the only explicit example of
this で in the book is 「ともやくんは宿題 **で** 人形を作った。」"Tomoya-kun made a figure for
his homework." on page 20.

So my three questions are: ① What is a definition of this で? ② How does 「宿題
**で** 作った」differ from に in sentences like 「朝食 **に** お茶を飲む」"drink tea for
breakfast" or 「お土産 **に** 葉書が欲しい」"I want a postcard as a souvenir"? ③ I found
two sentences below that I THINK fit into this category, but I could use some
confirmation that they are in fact the same で:

> この動画 **で** は、浅草で写真を撮りましょう。 **In** this video, let's take pictures in
> Asakusa.

> (JLPT N5 聴解 introduction) 問題一 **で** は、初めに、質問を聞いてください。 **For** problem number
> one, first, listen to the question.

[![enter image description
here](https://i.stack.imgur.com/1shHp.jpg)](https://i.stack.imgur.com/1shHp.jpg)




You know what 内容 means right? It means "matter" (content).  
で means "through", "along with", ... depending on the context,  
but here **matter + で** you can easily think of it as "on behalf of that
matter" or even easier just "about".

In your example the matter would be the desire to reach a higher school, and
from that you are going to consult your teacher.

Here's another example:

> 明日の試験のことで緊張してはいけません。  
>  _Don't be nervous about tomorrow's exam._

Again you can think of it as "Don't be nervous on behalf of that exam"

Hope it helps.

