Thanks for the link. "1983 BYTES FREE" - interesting.
Haha one whole whooping byte more than V2! I didn't notice that.

Oh thank you Manuel this helps allot!!

1) On the top of the page to the right of Mario there is a box with the red text "キーボード名キーの名称と使い方". I'm not sure what they mean.
Without reading everything I'm not sure either.

Without knowing any context I'd translate it like:
"Names and usage for the name keys on the keyboard."
名キーwould be "name key" if there's any keys like that.
Yeah I guess the context isn't obvious just from my post. The "red box" (I noticed there's not much red in it

) I'm talking about can be found in the top of every section in the manual and it usually ends with the "How to..."-like 使い方, 方法 and such. Since page 5 is a continuation of page 4 the "red box" can be seen as a reminder of what the current section is about.

There's no 名キー or name key unfortunately. I assumed they just meant that they are explaining what every key is called and how to use them. So my translation goes like: "The names of the keys and how to use them".
2)
On the bottom of the page where the explanation for the DEL key is: On the picture there are letters ABCXDE and to show how the DEL key works they want to delete the X. First it says to move the cursor to the character to the right of X and then it says "DELキーを押すと”X”が消え、”D”より右の文字がつまります。". Tsumaru means to block or clog according to the dictionary. I can't make sense of this.
"tsumaru" here just means that the other letters that come afterwards (namely DE) will "move up" i.e. there won't be a blank space where you delete the X. After deleting the X the text will read ABCDE and not ABC_DE.
Aha now I see! Allright I guess it says something like this: "By pressing [DEL] key "X" will be erased, and "D" and the other characters to the right will move up and cover the space."
P.S. it's always tricky to translate tech stuff. You have to know subj first.
True that!