Well, if you don't want to learn programming, then your best bet is to team up with a programmer. There are apps like GameMaker that let you make games without writing code, but believe me, it's still programming. You still have to tell the computer in great detail how you want every little thing in your game to behave; there's no way around that. And it's harder to do it by putting numbers one by one in a zillion little boxes.
And by 3rd-party assets I mean for instance pre-made tile packs you can use in your game, like you can find right here.