After your completion of GreedFall's prologue, one of your first tasks will be to speak with Constantin in the Palace of New Serene. After you've done this and you are leaving the audience chamber, Sir De Courcillon will ask for your help in tracking down Professor Serafeddin's notes on the strange Nadaig creatures.
This begins the "In Professor Serafeddin's Footsteps" sidequest, where you will need to find five collections of notes scattered around Teer Fradee, with there being 16 individual notes in total. Each time you collect one set of notes, you will earn 200 experience points, while completing the quest gives you 800 experience points and 250 gold. Here's where to find all of the notes you need.
Notes appear as the usual darker yellow glow of a collectible key item and will display on-screen once collected.
Notes regarding Nadaig Frasamen
(1/3) Magasvar: Fast travel to the Dididensen Camp.
The note can be found northwest of Dididensen Camp, on the northern edge of the map.
(2/3) Frasoneigad: Fast travel to the Roots Door Camp.
Head inside the Roots Passage and you'll find this note on the western side of the map. You'll need Level 2 Intuition to reach it.
(3/3) Frasoneigad: The other side of the Root Passage.
Fast travel to the Root Passage Door, then travel through the Root Passage and you'll find the note on your left as you come out the other side.
Notes regarding Nadaig Meneimen
(1/3) Magasvar: Fast travel to the Camp of the Stone Arch.
Head northeast from the Camp of the Stone Arch towards the east side of the map.
(2/3) Steiger falag: Fast travel to the Wenhsharvarr Camp.
You'll find the note on the northwest section of the map, just below the entrance to the cave.
(3/3) Meinei falag: Fast travel to the Daintnem Camp.
Head southwest of the camp and you'll find the note just north of the skill altar. You'll need Level 3 Vigor to reach it.
Notes regarding Nadaig Vedemen
(1/3) Magasvar: Fast travel to the Vighulgsob Camp.
You'll find this note north of the Vighulgsob Camp.
(2/3) Vedvilvie: Fast travel to the Swamp Sanctuary Camp.
The note can be found near the mural painted onto the rockface by traveling north from the Swamp Sanctuary Camp.
(3/3) Tir dob: Fast travel to the Swamp Entrance Camp.
The note can be found in a chest in the location shown above. You will need Level 1 Lockpicking to open the chest.
Notes regarding Nadaig Glendemen
(1/3) Glendgnamvar: Fast travel to the Didri Ruins Camp.
You can find the note in a ruined building just west of the camp.
(2/3) Vedrad: Fast travel to the Did e kiden nadaigeis Camp.
The note is in a ruined building southwest of the camp.
(3/3) Wenshaganaw: Fast travel to the Wenshsaveye Camp.
The note can be found close to the water just north of the camp.
Notes regarding Nadaig Magamen
(1/4) Glendgnamvar: Fast travel to the Vigamri Camp.
This note is found west of the camp we recommend that you fast travel to, close to the passageway leading to Bedri.
(2/4) Glendgnamvar: Head south from last note.
This note is just a little south of the last one, on the same path leading towards Bedri.
(3/4) Glendgnamvar: Head south from last note and enter Bedri.
Continue southwards from the last note and enter Bedri. This note can be found in the location shown above beside a skeleton.
(4/4) Steiger Falag: Fast travel to the Wenshavarr Camp.
Head east from the camp and you will find this note beside a body in the location shown above.
Don't forget to return to New Serene and speak to Sir De Courcillon to complete the quest.