How to implement this shopping cart's "Select All" etc via vuejs?

How to implement this shopping cart's "Select All" etc via vuejs? This is my demo： https://jsfiddle.net/kanjiushi/n4uujq01/6/

Screenshot：

Description： 1、Select all and cancel selecting all.

(1)When the checkbox "Select All" is checked, all the items below will be checked. And,when cancel "Select All", all the items below will be unchecked.

(2)check the items below manually one by one,when all the items are checked,the checkbox "Select All" will be checked. And, then,any one item is cancelled,the checkbox "Select All" will be cancelled.

2、The row "Sum" will show the summation of checked item(s).

3、When there is no any items checked,"Submit" is unavailable. When openning the page,in default,there is no any items checked,so,"Submit" is unavailable。

Another question： In my current demo,when I select the `Numb of one item, all the items' `Numb will be changed,it should be separated,how to make them separated?

Some help please,Thanks in advance!