Complex sentence: Nepal and Pakistan signed a protocol for establishing diplomatic relations in 1962 and exchanged ambassadors and set up embassies in 1963, when Ayub Khan, the President of Pakistan made a special visit to Nepal.
Split into simpler sentences: Nepal and Pakistan signed a protocol for establishing diplomatic relations in 1962. They exchanged ambassadors and set up embassies in 1963, when Ayub Khan, the President of Pakistan made a special visit to Nepal.