How to make lists in arabic to show from right to left

To create a multilevel list with custom numbering, for example with orientation from right to left, do the following:
1. On the Home tab, in the Paragraph group, click the Multilevel List button and then choose Define New Multilevel List...:

2. In the Define new Multilevel list dialog box choose the second level:

3. Delete formatting up to the first level:

4. Add the first level number after second level formatting:

5. Create other formatting (see Creating numbered lists).
6. Click OK and see new multilevel list.
See also this tip in French: Comment créer la liste numérotée en arabe pour afficher de droite à gauche.