Chris' answer is great. I just want to throw in something for you to think about concerning the future simple tense.
I think your grammar examples, from your book (?) are bad. Too many books teach "will" as a future tense, when in fact the use of "will" is more complex and subtle than that.(As a teacher of English to foreigners, this makes me crazy)
"will" is used most often when we are making a promise to oneself or to others in the future, or another way to say "be willing to (that is, be prepared to do something) " do something in the future.
https://www.ldoceonline.com/dictionary/willing
For example, in January, many people make resolutions to change in the new year:
I will lose 10 kilos.
I will read more books.
(S0, promises to oneself to do something in the future)
Promise to others:
A is your mother/B is you. You are leaving your mother's house and going home.
A: Don't forget to call me when you get home.
B. I won't (= I promise you that I will not forget, and that I will call you).
Willingness to do something (in the future):
A. I'm having a test next week. Will you help me study? = are you willing to help me? (do you want to do this and/or have the time and desire to do it)
If you look at the word "will" in the dictionary, you will see other examples of when it is used as a straight "I'm talking about the future here"
https://www.ldoceonline.com/dictionary/will