During your first 30 min of playtime other players can't damage you (except your team).
While the protection is active, a small HUD on the left of your screen shows the time left with a bar and the three key rules: other players can't damage you (except your team). The protection ends automatically once its playtime is used up. It ends at once if you attack a player yourself or own a ranged weapon.
"–" shrinks the HUD to one line, "✕" hides it (the buttons are clickable with your inventory open) – or switch between detailed, short and off with /noobhud. When the protection runs out, the HUD disappears and you get a notice. Move the HUD with /hud.
Commands
/noobhud/hud