The steps you need to take to volunteer at Habitat for Humanity Tucson

Habitat for Humanity is a international, charitable organization run by a Christian group. 
In order to volunteer at Habitat Tucson you'd have to do several things.
First, you need to sign up for the orientation here.
http://www.habitattucson.org/volunteer/
On the "Volunteer" section of the Habitat for Humanity Tucson section
you would need to click on either "Watch the Orientation" or
"Sign up."  "Watch the Orientation" is a tutorial online and you can watch it
there.  If you prefer going to the physical orientation itself, you would need to
sign up for one of the dates provided.  If you go physically, you can ask questions
or talk about other inquiries.

The second step is to sign a waiver. You can do that at the "Step Two"
section of the volunteer section. 

The final step is to make a account, sign yourself in, and then sign up
when and where to volunteer. You have that option of volunteering
at the Habitat construction site, or if you're not old enough or hate
doing labor work, you can always work at the HabiStore.  The Habistore
is great in that they sell new and used items to help restore or build a home
for a affordable price.