The nozzle opens by unclipping it using the tab on it. This exposes a ball shaped nozzle that comes out, do not drop it. The hose and ball are probably plugged with gunk. Pump some washer fluid through the hose using the end **** on the stick. Clean the hole in the ball and reassemble, align the jet with a pin in the hole in the ball.
Do not use plain water in the washer reservoir as it turns slimy.