dont try it,you should have some cutoff valves under the cabinet where the faucet is,just turn those off,to the right. then change your washers

Just turn off the valve under the sink, then replace the washers. You don’t have to turn off the main

Sure, turn the water off under the kitchen sink, there will be 2 taps (hot and cold) turn handles to the right till tight or it could have a slot fitting, if so, use a screw driver to tighten, after replacing washers, reopen valves.

Are They leaking now ?lol. . What do you think it would be like if you didnt shut the water off!! Make sure you have the size of Orings/washers you need before you start. . may need a stem puller too