Need strategy using offensive/defensive support?

You need to get the required number of points by getting kills, securing objectives, etc. Class is irrelevant When you get the required points (for example, first one is 50) the icons pop up in the bottom right corner.

50/50 points gets you either a Mortar strike or UAV. Pushing LEFT on the D pad gives you offensive support, RIGHT gives you defensive..

The key is to get kills. For every kill you get you get 10 points plus 5 for a headshot or you can get a tier 1 kill which is another 5 points along with kill assists which is also 5 points and every time you die your points reset to 0 and those points go toward your support. You get 2 supports(an offensive and a defensive support) every time you reach the number given. The first is 50 but to get to 50 you must kill some people.