Short answers, pulled from the story.
The war began when Regent Prince Abd al-Ilah fled Baghdad for RAF Habbaniya on the 31st of March 1941 after learning of a plot to arrest him. Rashid Ali and the Golden Square seized power in a coup d'état on the 1st of April 1941 and declared themselves Chief of the National Defence Government.
Iraqi forces left their bases heading west at 03:00 hours on the 30th of April 1941 and occupied the plateau south of the base within hours. Air Vice-Marshal Smart controlled the base housing around 9,000 civilians but only 2,500 men available for defense before attacks began on the 2nd of May 1941.
Between the 9th of May and month end about one hundred German and twenty Italian aircraft landed on Syrian airfields. On the 11th of May first three Luftwaffe planes arrived at Mosul under Colonel Werner Junck's command with an ultimate strength of between twenty-one and twenty-nine aircraft.
The 20th Indian Infantry Brigade known as the Euphrates Brigade advanced along the Euphrates by boat and road while the 21st Indian Infantry Brigade called the Tigris Brigade moved up the Tigris by boat to Kut. A third brigade of 10th Indian Infantry Division arrived at Basra on the 30th of May including battalions from Jat Regiment, Royal Sikh Regiment and Mahratta Light Infantry.
Faced with Clark's advance government Rashid Ali Grand Mufti and many members National Defence Government fled to Persia then went on to Italy on the 29th of May 1941. The terms quickly reached armistice signed on the 31st of May allowed Prince Abd al-Ilah to return to Baghdad as Regent monarchy pro-British government put back place.