Firing Range is one of the Game Modes in the game Squad. In training, players are left alone on an offline map of Jensen Range. This allows you to learn how to control your character and explore the map.
You can use almost the full functionalities of the game – most restrictions present in normal games are lifted, particularly the standard kit restrictions. Best use this game mode to get familiar with and set up the controls before heading into a multiplayer game and trying out the different roles and weapons. You might also want to make use of console commands like "AdminChangeMap" and explore the available maps.