The three met each other on September 1, 1991, when they were waiting in front of the Great Hall before the Sorting Ceremony took place in which everyone of them was sorted into Hufflepuff House. They shared a dorm together with Stiles Stilinski and Isaac Lahey.
Brody, Scott and Patrick have spent a lot of amazing and fun nights inside their dorm with Stiles and Isaac, but at the beginning of their fourth year, a change occured in their relationship and the three started to spend a lot of time together as a trio.
When Professor Posthuma announced in 1994 that auditions for the Music Club would be held soon after the Start-of-Term Feast and that one could not only audition individually but also in a group, Brody, Scott and Patrick decided that they would form a group and audition for the Music Club together. The following weeks, the three friends spent all of their free time inside the privacy of their own dorm in which they chose which song they would perform and, then, they started practising their dance routine. It took a lot of time to get everything synchronized but they didn't mind to put in a little bit of effort – that's what Hufflepuffs are best known for: hard work.
When it was time for their audition, Brody, Scott and Patrick walked onto the stage in the Auditorium (which was filled with Hogwarts students curious to see whether there was musical talent among them). They announced themselves as a group called the Supremes before performing the song "I Say a Little Prayer". Their audition and dance routine went flawlessly and Professor Posthuma, the director of the New Directions, allowed the three of them to become part of the Music Club.
The Supremes enjoy a good reputation within the school. Before Brody, Scott and Patrick formed the group, the three of them all individually were highly respected among the Professors and students because they're so kind and friendly to everyone and always willing to help someone in need, no matter which House they're from. Professor Sprout keeps referring to the trio as "the perfect Hufflepuffs" because they embody everything Helga Hufflepuff and her House stood for and Sprout knows she can trust them, because in 1993 she allowed Brody, Patrick and Brittany to host a weekly Karaoke Night inside the Hufflepuff Basement and there has been no incidents at all so far.
The Supremes have performed in front of many students multiple times and have shown to everyone how talented the three of them are and how amazing their voices blend in together, not to mention their dance routines are well-thought out and are always in perfect synchronization. Brody, Scott and Patrick even managed to gain fans and it's known that students, both from higher and lower years, have set up a fanclub in which they will discuss their performances, dance routines, and above all, their relationships and personal lives. The Supremes have acknowledged their fanclub and, on occassion, even go to their club hangout to give a private performance just for its members.
During their time at Hogwarts, the Supremes weren't the only group of students that enjoyed a great deal of reputation and fans: Quinn Fabray, Santana Lopez and Brittany S. Pierce, also known as the Unholy Trinity and members of the New Directions as well, were considered their rivals by fans, even though the members itself didn't see it like that. The Supremes and the Unholy Trinity could get along extremely well. The Supremes were all Hufflepuffs while the Unholy Trinity had a Ravenclaw (Quinn), Slytherin (Santana) and Hufflepuff (Brittany), the latter two of which are partners. For some performances the two groups even joined together and created one huge performance in which everyone got a chance to shine.
During an important performance in the Auditorium in which the New Directions battled against Music Clubs from the other magical schools in the region, the Supremes were allowed to perform a song together alongside the song they were performing with the New Directions. Unbeknownst to them, during their performance a reporter from the Daily Prophet was part of the audience and recorded the entire performance, about which he wrote and published an article of on the front page of the newspaper the next morning. This sudden and unexpected outing to the public made them not only famous inside Hogwarts itself but the entire Wizarding World, and this was before Brody and Patrick found out that they were both Elementals, which increased their fame even more.