On the first floor, it’s wrong to say that the A~Nylon string is a classical guitar practice guitar. It’s not enough to start with 20 days of steel string to change Nylon string for ballad guitar. 20 days of intensive training will bring a lot of fruits to learn ballad guitar. It’s no problem to sing simple songs. But music is certainly not a 1 or 2 day thing as a long-term hobby. If only 20 days, it’s better to ask the teacher to assist alone. Guide (or 2,3 people together) because the tutorial classes are not good, can not cultivate interest, basically all circle money, the teacher level is uneven, and can not be directed at guidance, especially not responsible.guitar is the simplest instrument, more practice will be many university talents, not too late, and the best singing point, because the guitar is very difficult to play finger-to-finger ballad solo at the beginning. But it’s fascinating and worth learning.