Complex sentence: By February 1945, constant provocations and insults directed at him by fellow JRV personnel due to his service with the ZNDH prompted him to apply for a transfer, and in April 1945 he was posted to the 1st Pilot Training School in Zadar as an instructor.
Split into simpler sentences: By February 1945, constant provocations and insults directed at him by fellow JRV personnel owing to his service with the ZNDH prompted him to apply for a transfer. In April he was posted to the 1st Pilot Training School in Zadar as an instructor.