How the skip sets up the shot: the broom as target, calling the turn, sweeping calls, and what the rules and federations say, so your whole team plays together.
The honest answer: in curling you often see the skip only as a broom at the end of the sheet, and that broom tells you where to aim. In the world federation's glossary, the skip is the player who directs play for the team [1]. In club glossaries, "line" is the delivery target and "Hit the Broom" means the stone is released directly on the skip's target, usually a broom [2].
How hard is it? Understanding is easy; coordination needs repetition. Here you learn what a broom signal means, how agreements work and why the broom isn't where the stone should end up. Important: in the sources I read there are no uniform hand signals. The rulebook doesn't regulate them, and a glossary doesn't list them [1][2]. What is listed below as hand signals is practice and must be agreed in your team beforehand.
The skip's broom marks the target line. Curling Canada describes the line like this: the stone starts straight and only starts to curl after the break point [3]. So the broom is not where the stone should end up but where you aim. How far off depends on the ice and the turn.
Milestone: You can explain to a teammate why your stone initially aims past the broom.
Point your toe in the hack at the broom, align hack knee and shoulders, and move the stone in a straight line towards the broom [4]. The stone barely shifts in this; mostly your body moves [3].
Before the throw, the skip says (or shows): which shot, which turn. Agreement matters, because the US federation's handout recommends that everyone on the team knows which shot is being played and that the skip ultimately decides [5]. Hand signals are a team agreement, not a standard (practice). What matters is that everyone uses the same ones.
Milestone: Before the game you spend two minutes going through all signs.
The US handout advises clarifying before the throw what is desired, what is acceptable (a "pro" miss) and what is not (an "amateur" miss) [5]. Example: on a draw, "a bit short" is better than "through the house".
"Hurry" is a call that tells the sweepers to sweep harder [1]. The calls are also team agreements. So the sweepers can react, they need the information before the throw.
If you don't understand the sign: ask at the start, not mid-throw. In the rulebook, the skip is in charge of the house inside the hog line while their team delivers [1]. There is time for a word between throws.
Treat the broom not as a point but as a lane. The national coaches recommend for advanced curlers the image of two lines, a lane about one broom head wider than the stone, rather than a single line [3]. Once you set yourself up on the broom like this, you relax and stay on line.
The skip directs play for their team [1]. They call the shot, hold the broom as the target and decide in the end [5]. Under the rules, they are also in charge of the house when their team delivers [1].
"Hurry" is a call that tells sweepers to sweep faster and harder [1]. It is a call within the team; what else the team calls it ("hard", "whoa") is agreement. Club glossaries define "hurry" the same way [2].
Not in the sources I read. The world federation's rulebook lists no skip hand signals [1], and the club glossary doesn't define them either [2]. The signs are team agreements. Agree before the game what "in", "out" and "sweep" mean.
No. Teams may not use electronic communication devices during a game [1]. A stopwatch is allowed if it only shows time data [1]. So you must settle signs and calls without technology.
Slide Position in Curling: Sliding Foot Under the Body, Leg Extended