My reference gathering for this project started by playing the remake games the level is based on (especially "Tomb Raider").
I gathered references from the same types of environments and how they were spaced in-game and wrote that down, I also looked for how they worked with their space.
The level mapping was made to give me a better view of how the level was going to get constructed before I started working on it.
The general layout map is to create a backbone to work from, this map helped me then to create the first iteration of the map on paper to give me a sense of space so I could start with the blockout.
First version of the level layout
The puzzles mapping purpose of the planning is to give me a road map of what will happen in that specific puzzle and what the player needs to do to get through it.