Have you checked the wiki's tutorials? https://www.warzone.com/wiki/Map_Making
They're in written form so you can go through them at your own pace.
As for Inkscape alternatives, any other program you can use to create SVGs might
be able to create an SVG that Warzone Maps use, depending on how feature-complete the programs are. (https://alternativeto.net/software/inkscape/
If you plan to check out one of the alternatives, consider going through the SVG requirements (territory numbering, being able to create bonus links as individual objects, etc.) to make sure the software can create the same type of SVG output that Warzone expects in a map.