Looking at the picture of the yacht you're modeling, you might wonder how you'll ever rig all those "ropes." You won't--you'll rig the shrouds, braces and stays of the standing rigging and the halyards and sheets of the running rigging. There are nine ropes aboard a ship and only one--the guy rope used to steady a crane--might be visible in your model. The rest keep the masts and sprits in place or just follow the flow of "working the ship."
Attach the shrouds from the side of the vessel to the top of the mast segment on your model yacht. Middle and upper shrouds are secured to the edges of the platforms built at the point where a new mast segment is added.
Shrouds are the lines that keep the mast from swaying side to side. If a mast is made up of several long pieces (as is a large sailing vessel, which has a platform where each piece is clamped atop another), there's a lower and upper, or lower, middle and upper part of the mast. This means there will be a lower port/starboard shroud, a middle port/starboard shroud and an upper port/starboard shroud.
Stays are the taut lines of the standing rigging that stabilize the mast backward and forward, running from the front of the vessel--fore--to the rear of the vessel--aft. Stays on a single-masted vessel begin at the center of the bow or stern end at the top of the mast.
On the foremast of a multi-masted vessel, the forestay will run from the bowsprit (the beam protruding from the bow) to the top of the foremast. The forestay and after stay of a mast between the foremost and aftermost mast will fasten to the mast before it and the mast after it, forming a criss-cross of lines between masts in a pattern called "cross-bracing." Multi-masted vessels also have topstays that run from the top of one mast to another.
Connect halyards (the lines used to adjust yardarms--the wooden crosspieces to which the sails are anchored--up and down on the mast) to the end of yardarms on a square-rigged model yacht (the sails are perpendicular to the center line of the hull) then down to the deck. Halyards are also attached to the end of each yardarm, then to the mast above the yardarm at an angle of no less than 40 degrees, and from that point to the belaying rack around the base of the mast.
Connect the braces to the same location on the tip of the yardarm as the halyard, then directly down to the main deck along the side of the boat. Braces "heave the yard around" the mast, changing the angle between the yardarm and the center line of the ship.
Attach the sheets from the loose corners of sails to the edges of the deck (along the sides) or, if run through pulleys at the deck level (usually on small boats) called fairleads, they are attached to a cleat (a t-shaped wrap-around deck fitting) at the control station.
Sheets are the lines that control the position of the sails, how much slack/play is in the sail and thus how "close" the ship is "held to the wind."
When building a ship model, do not splice the main brace because all the other rigging will go awry.