berpsie, good to ask if you don't understand what is happening. 2 teaspoons of dried yeast is pretty normal for 500 g bread flour, however if you add something like fruit for Hot X Buns you will probably have to double the amount of yeast. There are plenty of tried and tested recipes here so follow the instructions carefully and you also will have excellent results. That your bread rose even more with less yeast could be due to other factors such as a warmer room or the way you handled the dough. You will learn the more you make, so go for it and have fun.