To be savvy, to get it, to know one’s stuff, to be in the loop. Derived from the standard verb шарить (originally meaning to grope around, rummage, or feel around blindly in the dark), which evolved into a figurative meaning of navigating a topic well. Popular verb used to describe someone who is highly knowledgeable, competent, or perceptive in a specific field, subculture, or situation (он реально шарит в компьютерах — “he really knows his stuff when it comes to computers”, or ты не шаришь — “you just don’t get it”).
В настройках модема шарить надо
You must know your way about the settings of modems.
