Simple Lists
If you apply numbering with Format>Bullets and Numbering, you can choose either a Numbered list or an Outline Numbered list. If you choose a Numbered list, your list will be a simple single-level list.
A single-level list does not change its numbering style if the paragraph indent changes. There is only one level, and each paragraph in the list will have the same kind of number, regardless of the paragraph formatting.
However, a typical manual may contain a list of numbered steps on each page. These may all be members of the same list they may each be members of a different list.
If you select some paragraphs, format them with numbering, then choose Format>Bullets and Numbering, or right-clicks the list and chooses Bullets and Numbering, a dialog appears with two radio-button options: Continue Previous List and Restart Numbering. If you choose Continue Previous List, this list will be a member of the same list as the preceding list in the document that had that List Template applied. If you choose Restart, you create a different list.
When you start copying, pasting or moving paragraphs, you can move paragraphs from one list into another. This doesn't matter if all the numbered lists in the document are members of the same list. If you have multiple lists, the moved paragraphs can retain membership of a different list. Some paragraphs in a set of numbered steps are not numbering in sequence with the others. You get Spaghetti Numbering.
If you copy the paragraphs from a different document, they can't be members of the same list as other paragraphs in the destination document, because their list is not in the document. Word's answer is to copy their List Template into the destination document with them and insert it into the List Template gallery. If you then move some of these paragraphs around, you can produce some interesting effects. What you cannot do is guarantee that all numbered paragraphs with the List Number style will all be members of the same list and all number contiguously from top to bottom.