For this achievement you should find only
12 collectibles, but I will leave a video that will help you collect them all.
Credits: PS4Trophies Channel YouTube
Mission: Baku00:00 - Dog Tag 1/3
00:30 - Weapon 1/3
01:10 - Dog Tag 2/3
01:41 - Weapon 2/3
02:02 - Weapon 3/3
02:36 - Dog Tag 3/3
Mission: Shangai02:58 - Dog Tag 1/3
03:21 - Dog Tag 2/3
03:55 - Weapon 1/2
04:20 - Weapon 2/2
04:34 - Dog Tag 3/3
Mission: South China Sea04:52 Dog Tag 1/3