How do you turn on a bathroom sink?

Consult the person or company who installed it. If this is not possible, look for manufacturer name on the faucet and look them up on the internet for contact information.

If the faucet has two knobs the one on the left usually activates the hot water and the one on the right controls the cold water flow. Turing these knobs counter-clockwise usually initates the flow of water and clockwise shuts it off. Adjust both knobs to different settings to mix the hot and cold water flow together to achive desired water tempurature.

If the faucet has only one knob, it may operate by either pulling it outward to you or lifting it up. Rotating it to the left usually initates the flow of hot water and to the right for cold. A position in the mildle will mix the hot and cold water to offer warm water of varying degrees.

If you have a faucet designed differently than what I have described above, you may need to contact a professional plumber for further assistance.

Perhaps the installers neglected to turn the main supply on underneath the sink,(not really considered the Main supply, but I'll go with it!). These are valves that have an elliptical shaped handle,(probably chrome), and should be turned to the left, to turn on. Open the bathroom vanity doors, under the sink, reach in a with moderate force, try to turn on of them,(there will be one on the left for hot water, one on the right for cold), to the left,(counter-clockwise), and see if it turns. If it does, turn it all the way out, and do the same for the other one. If it's an issue on how to operate a new style faucet, perhaps you could call the place it came from, and ask them,(Lowes, Home Depot, etc.)

Well, you turn the knobs that are on the top, than if your sink is working right, water will come out.

tell it how beautiful you think it is and why you only want that sink, but it some flowers and try kissing it all over, rubbing it ever so gently. that should turn it on

Check the valves underneath that connect the water lines to the bottom of the faucet.

Rub its handles

Turn the handle....

like what do you mean by turn it on?

2 knobs

move the knobs