How to add contacts in during a campaign?

Hi. Just wondering how to add new contacts to an existing campaign ensuring that they start from email one of the campaign no matter when they are added?

Thank you

I would add a tag goal connected to the start, and add people by applying that tag. As for whether they will always start at the first email, it depends on if you are using Delay timers or some other timer. Delay timers will allow this without problem, date and field timers may not if the timer date has passed.