Complex sentence: After undergoing the preliminary course of study in these institutions, the children were sent to the kalaries for acquiring training in gymnastics and in the use of arms and then they were sent to study Sanskrit in Vedic schools under well trained teachers.
Split into simpler sentences: After undergoing the preliminary course of study in these institutions, the children were sent to the kalaries for acquiring training in gymnastics and in the use of arms. Then they were sent to study Sanskrit in Vedic schools under well-trained teachers.