In section 2, lesson 25, the dialogue includes a request for a "buena discoteca". I don't recall any examples where bueno/a preceding a noun before. Is a "buena discoteca" different from a "discoteca buena"? More generally, what is the rule for using buena/o before and after a noun.
In Spanish some adjectives can be placed before or after the noun, and "bueno/a" is one of them. The meaning is the same, but we tend to place it before the noun for more emphasis. So you can say "una discoteca buena" or "una buena discoteca". The important thing to bear in mind is that when the singular masculine form "bueno" goes before the noun, it loses its final "o" and becomes "buen": "Un buen restaurante" or "Un restaurante bueno". In certain set expressions "bueno" and "buena" are always placed before the noun, for example in "¡Buen viaje!" which can be translated as "Have a nice trip!". This is explained later in the program, in level 5.