This is really hard to deal with. I know you got a great heart. Firstly, I think is to see if we are financially sound ourselves. We need to be prepared to put in a lot of time in order to help the homeless. Maybe, one of the ways is to find out if they have any relatives. We can ask their relatives to help a bit.
Get donations to help built up at least a decent shelter for them. It won't be an easy task but I bet you've got a really big heart that's why you wanted to do this.
Humanity is saved.