The Qur'an tells us over and over again to obey God and obey His Messenger.
O you who believe! Obey God and His Messenger, and do not turn away from him. (8:20)
O you who believe! Obey God and obey the Messenger and those in authority from amongst you. (4:59)
It is not for any believer, man or woman, when God and His Messenger have decreed a matter, to have the choice in the affair. Whosoever disobeys God and His Messenger has gone astray into manifest error. (33:36)
Now, Qur'an only muslims, like those who run the submission website, will try to argue that the Prophet's example is only found in the Qur'an, and that the hadith we have today are fabricated. However, if we look at the muslim community following the death of the Prophet (saws), we see that they would often ask each other "what would the Prophet have done in this situation?" These consultations among the companions of the Prophet (saws) were the beginning of the ahadith we have today.
I would highly recommend
this website to learn about the hadith and their history, and also that you find yourself a good teacher who can help you with your studies. There is so much information out there, a lot of it bad or corrupt, and it's so easy for a new muslim (and even some who've been muslim all their life) to get lead astray.