This is maybe the more easy achievo you'll find here: you just have to read 10 notes during the main campaing.
Notes are spread all over the map, very easy to find, because they flash when you approach.
The very first is in the prologue, as soon you take control for the first time. Explore the house, turning right and you'll find your first note.
Get close enough to enable
button and keep pressed.
Repeat ten times and you'll get it... I've done in 20 minutes playing normally.
++ Note from MikeBugslayer: ++
you cannot read the same note 10 times, you'll have to find 10 different notes.