So, Music and Arts in my city is having a "garage band" contest, to where teenage bands write 3 original songs and record them to have them judged. And I'm completley cluless on to how to write music, like what chords should I use, etc. We are going for a rock theme, similar to Three Days Grace, Papa Roach, Breaking Benjamin etc. And try to create some catchy guitar/bass riffs. Are there any popular rock chord progressions? And if anybody has any tips or anything to help me have a better understanding for writing feel free to share.