Dia. 1
Dia. 1. The iron pillar
The 'side-by-side' extension of Black 1 is the key move. It makes a base for Black's stones, but more importantly, it eliminates any possibilities of White making a base for his own stones. Black's formation of two stones is usually referred to as an 'iron pillar'. It is quite effective in preventing the opponent from settling his stones.

Dia. 2
Dia. 2. Under attack
White has no choice but to escape into the center with 2. Back can then establish a stable position at the bottom with 3. In the meantime, White's stones are under attack.

Dia. 3
Dia. 3. Wrong order of moves.
Extending to Black 1 is an important move, but the timing is off. White can now slide to 2 and make a base for his stones. Black has to settle the situation in the corner before he can consider playing 1.

Dia. 4
Dia. 4. Good shape
When you are preventing the opponent from settling his stones, you will often have to be careful about making contact with any of the stones you are attacking. For example, the diagonal attachment is often a good move to make your opponent's stones heavy, but in this position it has the opposite effect. White first plays a hane with 2, then ataries with 4 and extends to 6. Suddenly, the marked stones along with the stones at 4 and 6 make beautiful shape.

Next —

Dia. 5
Dia. 5. Continuation
If Black now extends to 1, White will turn at 2, isolating the marked stone. On the other hand, if Black links up with 1 at 'a', or to the right of 'a', White will attack at 'b'.

Dia. 6
Dia. 6. Variation
Instead of Black 1 in Dia. 1, jumping down to the first line with 1 is also an effective move to prevent White from settling his stones.

Dia. 7
Dia. 7. Another example
White has just escaped into the center with the marked stone. At this point, there are no clear targets for Black to attack. With the fighting having come to a pause, this is a good time for Black to consolidate his gains by making an 'iron pillar' in the corner with 1. This move prevents White from invading at the 3–3 point and settling his stones in the corner.

Dia. 8
Dia. 8. A big opening move
Black 1 is a big opening move. It extends from his stones at the top and prevents White from extending from his corner enclosure. However, White will respond by capping at 2, cutting down on the scale of Black's moyo, then invading at 4.

Next —

Dia. 9
Dia. 9. Alive in the corner
Blocking from below with 1 is the correct direction. This way Black builds a wall facing his other wall below, resulting in a fair amount of territory. However, there is still a feeling that Black's stones are overconcentrated.

As for White, he has secured the territory in the corner and his marked stone may later serve to reduce Black's territory to the right.

Dia. 10
Dia. 10. A lukewarm attack
Black 1 seems to be threatening to attack the white stones below by capping at 'a'. However, this is not a severe threat, as White's stones are pretty much out in the open. White takes this opportunity to invade at 2.
Recomended Reading
More examples of preventing the opponent from settling his stones can be found in Chapter Two of Sabaki — The Art of Settling Stones.

Numerous examples and problems pertaining to the proverb 'Attach to settle your stones' can be found in Essential Go Proverbs, pages 447 to 461.