If you start to type in what appears to be a numbered list, Word formats your manually typed "numbers" to an automatic numbered list. The main benefit of this option is that you do not need to click any button to start numbering and you can choose your numbering style as well. For example, if you type "(a) some text" and press Enter, it starts numbering using the "(a)" format.
As you can see, the sequence name can be most anything (e.g. mySeq, A, B, or Bob's_your_uncle). If you start a sequence with a new sequence name the numbering restarts with 1. Look at Mary's first chore in the right hand column. Here you see the reset switch \r1 was used. This switch directs Word to restart the sequence named "A" with "1" at this point.
2. Yes, The code should be entered using CodeBuilder. Where you enter it depends on how and when you want to trigger the generation of the next number. If you want to use a button, that works. And no, you don’t use 000 in the NZ() function. If you want to DISPLAY at least 3 digits with leading zeros, then you do that in the Format function. Note, though, you will need to change that when you hit 1000 POs. sequentially numbering in publisher