You don't know how to make a hamburger yet, but that's not such a big deal. It doesn't take long to learn to make one.
What bothers me is that you don't seem to have a clear idea of what kind of hamburgers you want to make. Nor do you seem to have any idea of who will buy it.
Most people who succeed in the food business have a clear vision of what they want to make and who the think will buy it. I'm not telling you that you need to want to make the same sort of hamburger I'd want to; but that you need to really nail that down first before thinking of opening a restaurant/stand.
The product must always the first part of a business plan; and so far you don't have one.
I could tell you what kind of hamburgers I'd like to sell, how to cook them, and even give you some decent advice on how to market them -- but my idea of exceptional quality first last and always combined with fanatical attention to detail, might not be your particular vision.
You've got to narrow down what you want to cook, and figure out who will buy it, before shopping around for a lease and putting together equipment lists.
For instance, I'd like to: Grind my own meat daily from Choice chuck, round and bottom sirloin - 80/20; hand form 4 and 6 oz patties; single or double burgers; single or double patty melts; choice of four cheeses; chili; regular or grilled onions; ketchup, mayo, mustard, hot mustard, barbeque sauce, garlic aioli, and chipotle aiolis, demi-glace and red-wine reduction; garnishes would be the usual, plus grilled Anaheim chilis, bacon, and avocado; wheat or white buns with sesame, and sourdough rye (for the patty melts), all custom baked for the stand; splash the burgers with a mix of red wine and worcestershire and season with "basic California rub" before cooking on a char-grill. Sell them as ground beef steak instead of hamburger so that I could serve medium rare. "Belgian" style twice fried pommes frite. Locate to attract "Yuppies." So on and so forth, ad nauseum. You get the picture.
Now I'm not saying those are the burgers you should want to cook. Rather, that developing a clear idea is your job one. You seem to already have specific plans for each dollar of your first million in profit, and don't even know what kind of buns you want. If ever a cart was before the horse...
I certainly wouldn't invest a nickel in the product you've shown me, and my advice is you shouldn't either. Come back with a specific description of the hamburgers you'd like to sell -- and we'll talk.