The GLL Training Grounds is a practice concept that was introduced during the spring of 2018. It gives players of all skill levels the chance to practice with competitive server settings in PUBG.
The Training Grounds is a "click and play concept", where any team can show up at any point and join a game. As soon as 16 teams are ready, the game can begin.
Following an initial testing period, the format is currently being improved even further, and is set to return within the near future.