Below are the collectibles that can be found during the Halo Infinite mission called Foundation.
Skulls – Cowbell
Proceed through the level until you collect the Weapon. Keep moving forward until you enter a hallway and it talks about something behind ahead and calling out to it. Exit the hallway and then use your status button to locate the skull up in a rafter over the gap in the center of the room. You’ll need to use your grappleshot to reach it.
UNSC Audio Logs – Recovered Files 02 The Question
Obtained automatically as part of the story after finding the source of the signal.
Banished Audio Logs – Escharum’s Testimony 02 Cylix
After finding the source of the signal, you’ll get a new objective to head for the surface. Proceed forward until you reach a room where the weapon will have to raise a couple of bridges for you to proceed. The log can be found on a crate next to the door exiting the area. This will be after fighting a group of enemies using a plasma turret.
UNSC Audio Logs – The Prisoner 01 Not My Fault
Near the end of the level, you’ll need to find a power seed to power up an elevator to reach the surface. The audio log can be found to the left of the power seed on the ground in the room with the Forerunner containers.