Warm the body and the touch at the same time: quality passes to the correct foot, an open body to receive, and constant small movement. Raise the tempo as players get loose.
Mark a 15x15m square with a cone on each corner and a player on each. Pass around the grid one way, then switch direction on the coach's call. Start two touch (control and pass), then progress to one touch as players warm up. Keep the ball on the floor and pass to the receiver's back foot.
Warming up is a temperature problem before it is anything else. Muscle warms, becomes more elastic and contracts faster, and that is the physiological purpose of the first ten minutes. Static stretching a cold muscle does not achieve it and can briefly reduce power output, which is why a modern warm-up moves rather than holds.
What makes this particular square worth using with young players is organisational rather than physiological. Four players, one ball, four cones, and everybody is touching a ball within a minute of arriving. The alternative in most grassroots sessions is a coach explaining something to a circle of cold children, which wastes the part of the evening they are most receptive to and starts training with everyone standing still.
Raise the tempo gradually rather than starting fast. The first passes should be unhurried and short, and by the end of the ten minutes the ball ought to be moving at close to session pace. Going hard immediately is how a cold hamstring gets pulled in a passing drill, which sounds absurd and happens regularly.
Two technical habits are worth insisting on even here, because they cost nothing and they transfer. Pass to the correct foot, meaning the one that lets the receiver play forward, and open the body before the ball arrives instead of squaring up to it.
Do not coach heavily during a warm-up. The purpose is temperature and touch, and a coach who stops the square to correct technique has started the session before anybody is warm.
Save it to your private drills, then change the animation, adjust positions, swap equipment, or drop it into a session block. Or start from a blank pitch and build your own.