Short answers, pulled from the story.
The German invasion of the Netherlands began on the 10th of May 1940. The main Dutch forces surrendered on the 14th of May, and Dutch troops in Zeeland under French command continued to resist until the 17th of May, when Germany completed its occupation of the entire country.
A combination of severe military unpreparedness, a political culture that refused to treat Germany as a direct threat, and the devastating Luftwaffe bombing of Rotterdam on the 14th of May 1940 drove the Dutch to surrender. The General Staff knew it could not protect Dutch cities from further air attacks and ordered the army to cease hostilities. The Netherlands had almost no tanks, an air force largely composed of biplanes, and soldiers who had received minimal training before the invasion.
Fall Festung was the German plan, developed personally by Adolf Hitler, to capture the Dutch government, the High Command, and Queen Wilhelmina on the first day of the invasion using paratroopers landed around The Hague. The objective was to produce an immediate Dutch collapse. German officers were given lessons in how to address royalty in preparation. The operation failed: Dutch forces destroyed the incoming German transport planes at Ypenburg airfield and approximately 1,600 German airborne troops ended up isolated across the area without achieving their objective.
Hans Oster was a colonel in the Abwehr, German military intelligence, and a leading figure of the German resistance to the Nazi regime from 1938 to 1943. Beginning in March 1939, he secretly passed the date of the planned German attack to his friend Major Gijsbertus J. Sas, the Dutch military attaché in Berlin. Repeated postponements caused the Dutch government to become sceptical of the warnings. On the evening of the 9th of May 1940, Oster called Sas and said only "Tomorrow, at dawn," prompting a Dutch alert. Oster was later hanged after the 20th of July 1944 bomb plot to assassinate Hitler.
The Grebbe Line was the main Dutch defensive position, running along an Ice Age moraine called the Utrechtse Heuvelrug between Lake IJssel and the Lower Rhine. It was intended to hold long enough for reserves to arrive and mount counterattacks. It did not hold: SS troops from the regiment Der Fuehrer broke through the outpost line on the 11th of May and breached the main line on the 12th. Reserves that should have reinforced the position had been diverted to counter German airborne troops elsewhere, and mismanagement by Major-General Jacob Harberts further hampered the defence.
On the 10th of May 1940, twelve Heinkel He 59 floatplanes landed on the Nieuwe Maas river in central Rotterdam and seized the Willemsbrug bridge. The destroyer HNLMS Van Galen attempted to bombard the German-held Waalhaven airfield but was bombed and sank. On the 14th of May the Luftwaffe bombed Rotterdam, devastating the city. Germany then threatened to bomb other Dutch cities, and the Dutch General Staff, knowing it could not stop the aircraft, ordered a ceasefire.