I'm planning drawing a sea chart for a world of my creation for a D&D game. I would like to draw those lines and grids in the sea that, for what I understandm, are a tool for keeping a naval route while at sea. I want to try and replicate something like this map I found online but I don't quite understant how to appropriately draw those lines.

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Could someone who has a much better understanding of how these type of maps work help me with this project? What mesurements and points I have to track to appropriately draw those lines?

Thank you in advance for your time.