Pressing (Menu/Options) pauses your game and takes you to the Dossier screen. Use (LB/L1) and (RB/R1) to navigate between the different sections of the Dossier.
Mission
The Mission menu is the first and main section of the Dossier. Opening the mission tab shows you the map, in its current state of exploration, as well as the Challenges and Secrets that can be unlocked when traversing level to level. Interacting with an AutoMap Station gives you full access to the map for each level and displays the different types of secrets that can be unlocked, as well as their locations on this menu.
Arsenal
The Arsenal menu is the second section of the Dossier. Opening the Arsenal tab allows you to view all of the weapons you have currently unlocked, as well as functional descriptions and total enemies killed.
This serves as the weapon HUB for you through the campaign experience and the area where you can upgrade and customize each different weapon with the modifications of your choosing.
Praetor Suit
The Praetor Suit menu is the third section of the Dossier. Opening the Preator Suit tab allows you to spend research tokens acquired from Elite Guards, and view the current state of your Argent Cell routing, improved by finding Argent Cells.
You can spend your tokens on one of five different areas that increase the abilities of your Preator Suit: Environmental Resistance, Area-Scanning Technology, Equipment System, Powerup Effectiveness, and Dexterity.
Runes
The Runes menu is the fourth section of the Dossier. This tab becomes available to you after the first Trial Stone has been encountered and completed.
Completing Trial Stones unlocks the detailed Rune for you to equip. There are several to acquire and you can equip up to three at a time. Each Rune has a challenge related to the powers it gives, so try them all and harness them at their maximum strength!
Codex
The Codex is the fifth and final section of the Dossier. This tab continually fills with information about DOOM and the world around the Doom Marine.
The Codex populates as you encounter new demons and weapons, and scour the levels for Data Logs. The more acquired throughout the game, the more you understand the world around you. Find all the Data Logs to put together the pieces leading up to the awakening of the Doom Marine.