To get started, I’d take a look at what is already out there. Disaster relief is “sexy” in terms of aid (it’s quick and has fewer moral complexities than your average aid project,) so the field is pretty saturated.
After disasters, especially in very poor countries, all these foreigners come flooding in- and their efforts are not always useful. There are a lot of yahoos out there, and a lot of aid cowboys with good intentions but severely misguided notions who end up sucking up resources, adding to the confusion, and not really helping much of anyone.
After the tsunami in Thailand there were people bringing in stuff like baby bottles and diapers (which rural Thais generally don’t use) and bales of winter clothes that nobody wanted (and which then rotted in the rains and became breeding grounds for disease) and piles of food that depressed local food markets and made it impossible for poor farmers to recover. Unqualified or semi-qualified people came in offering dangerously inadequate physical and psychological health care with a worrying lack of follow up support- people might get one shot in a series of inoculations, and not have the structure to know or get the complete care they needed. And all these extra people clogged up infrastructure and resources that were desperately needed by others. In other words, there are some very good reasons to take the planning of what you are doing very seriously. Sometimes nothing is better than something.
If your goal is to make the maximum positive impact, you are going to have to do some honest examination of what you can do with the money versus what that money could do in an already existing organization such as the Red Cross. Poor communication between aid providers, service overlap, and projects that end up competing against each other are a massive problem in aid and waste millions. It’s irresponsible to start a project without making sure that you really do have something to offer that can’t be done better elsewhere. The existing organizations (Red Cross, Doctors without Borders, etc.) have spent years putting their infrastructure in place. It’s a waste to completely reinvent the wheel every time someone wants to do good, simply because someone wants to feel like they are in charge.
Once you have done this research and determined what you can contribute, then contact a professor of humanitarian assistance for literature recommendations. The UN and most of the major organizations put up all their literature (including best practices, evaluations of previous efforts, etc.) on the web for free. You can learn from that. There are decades of rigorous studies (and theory to compliment it) trying to suss out exactly what does and does not work. Get a working familiarity in the field. Then you will want to start working with some professionals (or getting some professional knowledge) regarding designing aid projects. There is a whole set of lingo and some key tools you will need to be able to learn to be taken seriously in the field.
I’m not trying to burst your bubble, but rather encourage you to dream in a constructive way. One person can make a huge difference, and lots of world-changing projects have started with a dream. But it’s equally true that anyone who can scrape up money for a plane ticket can start thinking they are going to be able to help out, and unfortunately that isn’t true. If you are going to think about how to do this, you have to think from the beginning about how to do the best possible job.