In pursuit of his ambition he worked hard

In pursuit of his ambition he worked hard. We had to give him credit for that. He borrowed training manuals and stayed up late at nights reading them. He badgered the instructors with questions.
(a) What was the Professor’s ambition?
(b) How did he want to achieve his ambition?
© What is meant by the word ‘badgered’?

(a) The Professor’s ambition was to become an army officer and as a first step, he meant to get a stripe.
(b) He wanted to achieve his ambition by working hard by reading training manuals in spare time, asking more questions, drilling with enthusiasm and behaving like a model soldier.
© It means.‘pestered’.