The first week wasn’t especially important but it was part of a very short arc that saw Hitler go from opposition political leader to absolute dictator in a series of steps. The Depression in Germany splintered public opinion. This led to a very unstable legislature in where no one party could govern effectively. As a result, there was an increasing reliance on government by emergency decree by otherwise mainstream parties. This established norms for authoritarianism and anti-democratic behavior but had little to do with the Nazis. They were just a growing opposition party at this point, seen as outside realistic voting options for most.
Hitler announced he would only seek power through elections in 1931, which helped solidify him as a viable political choice for the middle class, capitalists, military officers and other conservatives. Before that, Hitler and the Nazis were seen as ruffians outside the pale of good taste that appealed to angry violent yahoos.
Hitler came a strong second in the January 1932 Presidential election to Hindenburg, and remained leader of a large but not in any way dominant political party. The Nazis were one of numerous parties in a highly fractured legislature. More parliamentary elections were held in July and November of 1932 but there was no ability to form a majority government that was stable, and the minority administrations were rudderless.
After the November elections, a number of leading politicians and wealthy men appealed to President Hindenburg to appoint Hitler Chancellor in order to get stability. In January 1933, he came to power in a coalition with just three positions for the Nazis but critically, control of the police.
That first week wasn’t especially profound. But Hitler quickly dissolved the legislature and called for new elections to be held in early March. Calling of the elections wasn’t especially crucial. February 27, 1933 was crucial: The Reichstag building was set on fire. A Communist was found inside in incriminating circumstances, accused of the crime by the Nazi policing minister and the resulting political crisis gave Hitler the excuse to issue the Reichstag Fire Decree. He suspended basic rights and allowed arrest without trial. Mass arrests of communists and political opponents were combined with political violence and intense anti-communist propaganda.
There is a near consensus that the fire was the work of that communist. There is a minority view that the Nazis had a role in setting the fire and framed the communists to give them the excuse to issue the decree and polarize the election against the communists. Either way, the fire gave Hitler the excuse to issue the decree and that was act that got him a dictatorship.
The Nazis came short of a majority in the election. To remedy this, they proposed legislation giving Hitler a 4 year temporary dictatorship. This required a super majority in the House, and they didn’t have the votes. So the Nazis used the Reichstag Fire Decree powers and their control of the police to arrest the communist members of the legislature. They also detained some of the Social Democrats and physically intimidated others. They created so much chaos and intimidation, and took away so many opposition votes, that they made their bill viable.
On March 23, 1933, the Reichstag voted to grant Hitler those “temporary” powers to enact laws without the consent of the legislature. From here they expanded their campaign to outlawing the Social Democrats as well as the Communists, then dissolved all trade unions. Political opponents were sent to the concentration camps. By June, all other parties had been intimidated into disbanding.
The first week in power wasn’t that important. But democracy was completely dissolved within five months of Hitler assuming office and Germany turned into a one-party state that jailed and murdered opponents.