Start with a reproducible seed
The seed creates an original arrangement of water, plains, forest and mountains. It is a starting point rather than a simulation of real climate or geology. The same seed reproduces the same initial terrain and locations.
Pick a world-distance scale before placing routes. Each cell represents that many fictional kilometers. The scale bar communicates this world convention; it is not a promise that a printed page has a particular physical map scale.
Paint with a clear purpose
Terrain changes the route graph. Regions add a colored political or narrative layer without changing travel cost. Location markers identify named places and can be marked as game-master secrets. Keeping these roles distinct makes later edits easier to understand.
Use the pointer or enter exact X/Y cell coordinates. Undo restores earlier map states, and the starting-map control returns to the original submitted world. Regenerating a seed is also an undoable edit.
Keep the project as the source
The project JSON preserves cells, layers, names, visibility flags and route endpoints. Handout exports are views of that model, not substitutes for the editable source.
Save after meaningful changes. There is no account, automatic browser backup or remote project store. A local download is the explicit record you can reopen later.