Let's look at the purpose map.

Our big purpose is in something, that will help people in future.

Why do you need it? It will not benefit you directly, at least not as much as engaging in business ventures.

It is a good question. Someone could say, that people donate their stuff to Goodwill just to write it off their taxes or unclutter their garage. Someone could say, that people volunteer to socialize or to entertain themselves.

The Big purpose is not about gaining maximum direct benefits. It is about managing risks and minimizing possible losses. We do it because we see the bigger picture, we feel ourselves as part of our community and part of our World, and we care about our distant future.

It does not make practical sense to invest much time in building a sandcastle just to see it washed by the high tide. But imagine a town where kids are not protected from drugs. They all will eventually become addicts and die from overdose, and town is doomed to become a ghost town. So what is the difference in investing time in sandcastle and investing time in teaching math in this doomed town? The only difference is scale.

We are willing to invest our time in the future of our community and future of our World just to protect all the efforts we put into it. Otherwise it just does not make sense (unless, of course, we don't care whether we work for future good or for trash can).

Now when we see that we need to do something, let's analyze what can be done, and how do we get maximum out of efforts we can put into. Remember, we cannot put there all of our efforts. We need to achieve our minimum purpose too!

Then let's look around. There is always some picture you see, and some bigger picture behind the scenes. You see, that we have serious ecology. So you can save electricity and recycle, or you can join some Greenpeace guys.
If you see the picture, you see the machine, that burns resources and makes waste. You try to make it burn fewer resources and make less waste, which sounds quite reasonable.

But if you see the big picture, you would rather invent some resource-creating technology - some machine that creates new resources instead of waste on the way forward. Well, not just new resources. In the perfect World it shall create something that we will need on our next step, many years from now.

It is clear how to deal with the picture we see. But how can we learn to see the bigger picture, and where do we study resource-creating technology design?

First, resource-creating technology is just one of big things. There are two more need to be created. First is pushing molecular biology to the level where it can repair any problem in human body including aging. Second is Strong AI. It is not obvious why do we need a Strong AI. Molecular biology tied up to resource-creating technology will give endless source of supply to human World. There will be no motivation to move forward. Strong AI will require a lot of efforts to raise. Yes, it will be very smart and very fast, but still it will be a kid that need to be raised to adult mindset. Hopefully, humans get motivated to put some resources into the new "kid" rather than burn 'em themselves. Hopefully, with all these advantages we will be able to walk through the technological singularity. How exactly we are going to do it? We will see when we get closer. It does not look like there is a practical way to avoid it.

Now how and where do you learn those things? If you know - please tell me. I personally have access to knowledge that is not available to general public and, unfortunately, not well structured. I put lots of efforts into studying it, but learning curve is very steep. I already put some of it in simple Russian and published on http://nachni.com My plan is to translate it to English and publish on PurposeMap. However, there are few things you can do yourself. First, study the history. Check out how human civilization changed. Check out how was changed what people think of themselves. Find out the root cause of these changes. Second, read masterpieces of the World literature. Find out when characters changed, when they had to make decisions, what was pushing them forward and what was blocking them, how their aims evolved, how what they think about themselves evolved, and how it all work together.
 
Now back to the Big Purpose.
It will be great when you learn to see the bigger picture. But not seeing it yet is not an excuse for doing nothing. There are lots of thing waiting to be done. Please go ahead and make a difference. How can you help to secure the future of you community and the World? You can start with some risk analysis, like this one:
http://www.nickbostrom.com/existential/risks.html