If you have the inlet on the top, you have a bladder tank, if it’s on the side you have a bladderless tank.

Either way, there is a “bicycyle valve” on the side which is used to partially fill the tank with air. If it is a standard 40/60 tank you turn off pump, drain tank and then refill with air to about 39 pounds, then turn the pump back on.

If you have NO PRESSURE at all, then the well pump is shot.