Beamographic
Beatmap Editor
not sure if this is really the place to ask but where do I access the map that was made with this game mode in mind I want to start mapping for this mode but I have no real idea how it works.
Unfortunately those maps no longer work with the rewritten beatmap conversion. I don't think it's currently possible to manually select the target game mode from the lazer beatmap editor, or even select "new beatmap".
What I might be able to do as a temporary measure is allow the ruleset to revert to the old conversion method if it detects a particular tag in the beatmap. You would need to make your maps in the stable beatmap editor and manually import them into lazer.
Once the lazer editor is more complete it should be fairly trivial to choose "New > Rush! Beatmap" and have an editor layout similar to gameplay.