I'll try to tell you guys how actually they are in their each roles in Glee.
Let's get it started from Glee's coach, William Schuester!
William Schuester, commonly known as Will or Mr. Schue, is the teacher who took charge of the William McKinley High School Glee club, New Directions. He is the main protagonist of the series. He was married to Terri, but then he discovered she was lying to him about being pregnant, and he divorced her. Will is portrayed by Matt Morrison.
She is the diva of New Directions and has defeated Sunshine Corazon, Kurt Hummel, and Mercedes Jones in diva-offs. She was raised by two gay fathers (she doesn't know which one is her biological father). Rachel appears to be unpopular with most of the other students because she is known as a freak in fashion and way too ambiguous. She is typically very competitive and often shows 'diva' behavior by always wanting to be in the spotlight and be the center of attention due to her dream of becoming a famous STAR. Rachel Berry is portrayed by Lea Michele.
Finn Christopher Hudson is co-captain of the glee club, New Directions together with Rachel Berry as the captain, Finn is also the quarterback of the WMHS Titans Football Team. Finn is portrayed by Cory Monteith.
Mercedes Jones can best be described as a diva. She loves to sing and had a close relationship with her friend Kurt and was the first one to find out he was gay. Since Kurt has transfered to Dalton Academy , Mercedes has been closer friends with Rachel. Mercedes is portrayed by Amber Riley.
Noah "Puck" Puckerman is a member of both the glee club and the football team at William McKinley High School. Puck is portrayed by Mark Salling.
Kurt Hummel is a student at Dalton Academy, a member of the Dalton Academy Warblers, and former student of William McKinley High School, the New Directions. In Season 2, Kurt transfers to Dalton Academy due to being bullied by Karofsky. He is currently in a romantic relationship with Blaine Anderson. Kurt is portrayed by Golden Globe Award winner Chris Colfer.
Quinn Fabray is a member of the New Directions and former member of the Cheerios. She is known for good looks and extreme popularity. Quinn and boyfriend Sam broke up because she kissed her ex-boyfriend, Finn, who she is now back together with. Quinn is portrayed by Dianna Agron.
Santana joins the Glee Club to spy for Sue, but soon develops a love for music and stays of her own volition; in mid-season two, she quits Cheerios in protest over Sue's lack of regard for the girls' personal safety. She is a closeted lesbian and is in love with her best friend, Brittany Pierce. She is portrayed by Naya Rivera.
Brittany Susan Pierce is a New Directions member and a former Cheerio. She is very popular and was one of the top Cheerios. She initially joins the glee club to spy for Sue Sylvester. Brittany is portrayed by actress Heather Morris.
Arthur "Artie" Abrams is an active member of New Directions and is a student of William McKinely High School. He is currently dating the cheerio Brittany S. Pierce. Though he is in a wheelchair, Artie refuses to let anything hold him back. Artie is portrayed by Kevin McHale.
Tina Cohen-Chang is a member of New Directions. She is known for her unique Goth fashion sense. Tina was formerly the girlfriend of fellow glee club member Artie Abrams, but she broke up with him since he used to treat her badly. She is now dating Mike Chang. Tina is portrayed by Jenna Ushkowitz.
Susan "Sue" Sylvester is the coach of the cheerleading team, the Cheerios, and detests the Glee Club and their teacher, attempting to bring it down at any cost. Sue is the main antagonist of Glee, and is often seen as the teacher who shakes things up. She is constantly bullying other students, faculty, and Cheerios, but manages to be one of the funniest characters of the show. Jane won a Golden Globe for Best Supporting Actress In A Comedy Musical and/or TV Show, she also won an Emmy in the same category.