1. I need to have more than 1 rule active at the same time. Is it possible?
Yes, you can have more than 1 rule active at the same time. In fact, you can have as many rules active as you desire
2. How do I add a rule?
Select from any of the categories available. For more information, see this article.
3. Is there a way to prevent certain orders from being auto-tagged?
No, there is no way to prevent certain orders from being auto-tagged. Instead you will have to manually delete the tags.
4. Will previous orders be automatically tagged after setting the rule?
Previous orders will not be automatically tagged after the setting of the rule; only new orders from henceforth will be affected by the ruling.