Same way you'd bootstrap if you needed developers, and couldn't afford to hire developers. You can either study and try to do it yourself, you can offer equity (although lawyers are generally smarter than developers in this area, and few will take just equity, but you might be able to find someone), or you do it the old fashioned way and get a small business loan from a bank.

Although, as has been said, you don't need an LLC if your business is not "there" yet.