Stuck at Chapter 3 after cutscene with assistant

[lampa]

Before going down the bunker , I finished off the guys beside the cannons , shoot abit the phantom that appear which then dissapeared , and then went down the bunker .

After the cutscene , I got the red thingy inside the room but from there , I'm stuck .

My main objective is to get to the top of the hill , but I seen no ways to do so . There's an unlimited supply of bomb thingy beside the artilary cannon but I can't find any use for it . I tried bombing everything I can and shoot everything I see but still stuck .

Please please help !

EDIT: Solved myself . I missed some stairs beside the room with the switch that enable player to ascend to the area with cannons . Lock topic please.