Well, after carefully reviewing the provided context—which consists of YouTube's corporate information and a link—I can confidently say it's about as useful for cleaning your sofa as a screen door on a submarine. So, let's set that aside and use some actual know-how.
Ah, the dreaded water stain. It’s a cruel joke from the universe, isn't it? The very substance we use to clean things decides to leave its own ghostly calling card on your upholstery. The stain isn't really the water itself, but the minerals and dirt it stirred up and left behind as it evaporated. To defeat it, you must paradoxically fight water with more, better-behaved water.
First, consult the ancient runes, also known as the cleaning tag on your sofa. If it says 'W' or 'W/S,' you're in business. If it says 'S,' stop right here and use a solvent-based cleaner, as water will only worsen your plight. If it says 'X,' you can only vacuum it and perhaps learn to love the stain as a unique design feature.
Assuming you got the green light for water, grab a clean white cloth and some distilled water. It must be distilled; using tap water is like trying to put out a fire with gasoline, as it just adds more minerals to the mix. Lightly dampen the cloth and blot the stain from the outside edge inward. Do not scrub! We're gently persuading the stain to leave, not angrily scouring it into a bigger mess. You want to feather the edges, slightly dampening the area around the original ring to create a gradual transition and avoid a new, larger watermark.
The drying process is critical. Letting it air dry is an invitation for the stain to return. Use a hairdryer on a low or cool setting to dry the spot quickly and evenly. Keep the hairdryer moving to prevent any one area from getting too hot. Once dry, the ghost of spills past should be gone, leaving your sofa looking respectable once more.
