These two questions draw attention to the amazing self-sufficiency of God. The answer is of course that no one gave God anything or appointed him, but the questions teach us to marvel at the way God works alone, independently of all others.
Because our thoughts are so finite, we naturally conceive of a God who is limited and we can only advance to a true understanding of God but repeatedly reminding ourselves that he is not like this, not like that. This thinking process stretches our minds and it is the way Elihu leads us to consider the greatness of God. There is no one to whom he is accountable for his work, but he works sovereignly. He is before all things and he made all things. There never was, when God was not. Therefore he and he alone must take credit for all things. Nothing has happened by chance or by luck, but all has infinite planning behind it. He is rightfully the Lord of all and is constrained by nothing other than his own perfect character, which is not in fact a constraint, but perfect freedom.