This is a Double Assault game with two neutral Capture Points. The best way to ensure victory is to quickly take control of the Capture Point on top of the dam. The lower Capture Point can easily be taken by parachuting down from above and attacking. On top of that, the lower dam does not lead to a good means of attacking another Capture Point since it is at the lowest area on the map.
Once you have secured the upper part of the dam, work towards taking over the lower. Do this by launching multiple attacks. Have part of your team parachute down to attack the lower dam while the rest of your team attacks the main base. The main base attackers probably won’t succeed, but it will be a good diversion and help you to secure the lower dam. Once you do, you’ll have a ticket drain. Each of the team’s starting CPs are extremely difficult to capture. Be content to hold down three Capture Points and drain the opposing team’s tickets. Once you have them into just one Capture Point, keep them holed up in there with constant fire. If you find they are mounting a significant counter attack, consider destroying parts of the dam to make sure they can’t roll across with vehicles and gain a foothold on the dam.