To obtain the Diaries of the Dead side quest in Dead Island 2, speak with W.O. Rodriguez in the Tower at Venice Beach. Afterwards, head to the convoy in the center of the area.
Once there loot the Memory Stick for a crate next to the middle truck.
Once you loot it, you’ll need to persevere through the waves of enemies. Finally the Signal Officer will spawn. Defeat him then loot the Comms Area Keycard. Afterwards, advance to the USMC comms area to find the Satellite Dish.
Insert the drive into this satellite dish. While it uploads, you’ll have to fend off the zombies again. After the first wave, the upload failed so interact with the dish to see what happened. Afterwards, report back to Rodriguez at the Tower to complete the quest. As a reward, you’ll receive 3,500 XP and Burst-Fire Carbine.