I don’t have any resources, but I have used story-telling to help people get past their fears - talk about it, talk about the good experiences, and acknowlege the bad experiences, and the funny experiences.
The other thing that is very effective is to set the example. If the opportunity presents itself, take the group to Confession, and be the first in line. Tell them with your actions that you see this as something very important to do.
There are also some people who don’t want to get past their fears, or who genuinely don’t think they need to go, and there’s not much you can do about that.
My pages on Confession for teens are HERE and HERE