Hey Gamers! Welcome to NHL 19 World of CHEL!
Video below if you prefer video!
***Some players are reporting that the achievement did not unlock with the first back opened, if that is the case just progress your CHEL character a little (only takes one game) to get your first progression awarded bag and opening this should unlock the achievement***
It doesn't get any easier than this, and consider this a FREE achievement. You will have a "goodie" bag to open as soon as you launch the World of CHEL mode for the first time.
These hockey bags are essentially cosmetic items that you unlock by simply playing games with your World of CHEL character. The first bag you open, and you will open a bunch, will net you this easy achievement.