You will get dropped onto a road. Move up ahead and fly over the roadblocks, onto a roof and take cover. Trying to be on the ground will get you killed without excessive pre-killing.
Begin with taking out the enemies that can shoot you, AKA the ones on a similar altitude.
Then move onto the ones that are on the ground, visible to you.
Once a decent amount has been killed, go take the control point in the middle of the base.
A small tip is to also keep an eye out for these flying drones. They will not be marked on your hud and will not be shot by your friendly soldiers for some reason. If left unchecked, they will repair the turrets you destroyed, leaving a possibility for very nasty traps.
Once the CP is captured, you will need to defend it for a couple of minutes. Enemies will come from all directions so stick close to the point.
Enemies will often have their backs turned while approacing the control point. These are golden opportunities to 1-hit kill them with your knife from behind.
Take a breather whenever possible. The enemy will attack rather vigoriously.
You will also eventually run out of ammo. When this happens, make a dash for a nearby supply depo.
There will be several nasty lieutenants lurking about. Locate them all and take them out one by one or watch them kill you through your shield.
When you are confident that most enemies are dead, go ahead and move up to the objectives and plant explosives on their hardware. You will sometimes have to look for the sweet spot before bring prompted any interaction but it's usually easy to find thanks to the HUD markings.
When done, move up to the row of heavy armors and jump into one.
This will introduce your first ride in a heavy-mech (Unless you have purchased one before). Use (F) to spam highly damaging melee swings and/or grab hold of nearby infantry that are infront of you and space to leap a couple of feet infront of you.
Have a long walk with (unfortunely) no sprint function in the heavy mecha and start cleaning out the enemy base.
There will be other enemy heavy mechas around. Deal with them by getting close & personal while spamming your melee.
Nearby infantry will be the only viable thing to shoot with your arguably useless machine-guns while in the heavy mecha. Clean out the place throughly.
Eventually, a tank will jump into the fray. Quickly get close to it and smash it into bits while circling around it, avoiding the main cannon.
When done, get out of your heavy mecha by using E and capture the control point.
While capturing it, a few more enemies will most likely surface, being hidden earlier. Take them out and once you have captured the CP, the mission will end.