1. How can i track the item a player is using/throwing (c4) and the amount of times used?
     
  2. For timed explosives you could use
    Code:
    void OnExplosiveThrown(BasePlayer player, BaseEntity entity)
            {
                if (entity.prefabID == 498591726) //c4 item id
                //collect your information here
            }
    Hooks like this are in the docs, you should check it out Oxide API for Rust