Great to hear you're enjoing the lessons, and fire away with those questions, please!
A quick way to say that would be a simple "tweede straat links/rechts" no "take" required - but you could also say something like "neem de tweede straat links/rechts"
Your answer is better than mine, well done The answer in the lesson is, like Aran said, more like "must/have to/got to learn more". A hiccup, almost certainly caused by the subtle difference between "I've still got more to learn" and "I've still got to learn more", I'd say. In a conversation, it would not matter which of the two you use - the difference in meaning is that close.