I have done this a couple of times, for victims of earthquakes in Greece.
First of all, be prepared that you will see things you won't be able to forget and along with your stuff pack your courage and energy. Other than your help in building, storing, assisting in any way, you will be asked to provide emotional and psychological support to these people. I remember the first time I went to help others like that, I came back in 3 days. I couldn't stand the crying and the misfortune. But I went back again after a while.
Here are some tips:
-In places like that you must pay extra care of your personal hygiene. Before sleeping at nights make sure you clean your skin with dettol or something like that. When you go to the bathroom, make sure to touch everything as less as possible. Oh, take toilet paper with you, there's a high chance you won't find that if you won't be staying in a hotel.
-Carry with you always your personal stuff of high value and if you have to leave stuff in the tent/room, make sure you secure them with a lock. Poverty can drive people to do things they wouldn't imagine themselves doing.
-Don't take with you anything of high value anyways and pack lightly.
-Respect the culture of the people you will be with. In smaller communities a modest behavior is to be expected by everyone.
-Be very careful when taking pictures, some people don't like it.
-Always go to the leader of the trip when something unexpected happens, don't take light decisions, let someone else more experienced to tell you what to do.
And, finally, i will put this lightly: What you do is noble but you can't be sure that everyone will be there to really help these people. So, keep your eyes open -for you and for all others-.
I hope you'll have a great time there, please let me know how it was when you get back <3
From now on, when you hear someone saying "Who cares?" you'll be able to reply that you do. It's an amazing feeling