Control points are shown on the map with a ring around the weapon's area, and on your HUD with a waypoint, using the weapon's icon as an indicator, showing the direction, who's in control (Red: Locust, Blue: Cog, White: Neutral), and how many of the 60 points (given at a rate of 1 point/second) are available for the taking. After the points have been distributed, another "Hill" will be randomly selected next. The speed at which a team gains control of a "Hill" is dependent on how many member of the team are within the ring on screen. A full team can capture in 1 second, three in 2 seconds, half your squad in 4 and a lone cowboy with his chainsaw in 8 seconds. Once you capture it, you can defend it from wherever you see fit on the map, you're not restricted to staying in the ring of death.
The gametype is still round-based, and rounds are won when a team reaches the host determined number of points. This can be somewhere between 120 and 480 points, with increments logically being multiples of either 15, 30 or 60 points. Annex can be played in both player and ranked matches, which brings us to our next thought. How will this affect the "Seriously..." Achievement? Couldn't a group theoretically ignore the control points and simply frag each other until the cows come home? That being said, playing legitimately also seems to be an answer to expediting the process, especially if you have 19 round games at 480 points per round.