First, you need to properly set up your numbering attached to styles as set forth in Shauna Kelly's article.


You need a level one, perhaps with no number. When you apply the style associated with that level one, the rest will restart by default (although you can set them to not do that).


That is, your current level 1 has to become your level 2 in the properly set up multilevel list. Then, you can use the new level 1 to trigger restarting the rest of your numbering.


I know that this is almost certainly not what you want to read. Microsoft needs the higher level to trigger restarting automatically. That is how it is.