Chapter 4: History’s Ember has loads of collectibles. Including Optional Mission, you can find 5 logs total (including rumored 3 more that you can get only by doing Co-op missions) during this chapter.
Luckily most of them are easy to find, but for some you might find our screenshots below helpful.
Text Log no.1
The first log is right there, next to the workbench, as the Chapter starts.
Audio Log no.1
As soon as the cutscene in the Admiral’s quarter ends you can turn around and the audio log will be there, up some steps.
Text Log no.2
You will find the 3rd Log right of the previous audio log, on a table nearby.
Audio Log no.2
Next audio log can be found as part of an optional mission taking place on C.M.S. Greely. Your main mission tells you to go to Terra Nova, but instead you can take the shuttle to C.M.S Greely. The first Log you will find here involves solving a puzzle on a fuse box down in the communications room. Once you solve the puzzle, the audio log will start to play automatically.
Audio Log no.3
As you progress through C.M.S. Greely you will get to a room where you shut down the electricity and fires start coming from the floor. At the end of this room is where you will find the audio log, next to Engstrom’s Office Key you need to continue the Optional Mission.