An RPG maker should be tested through a playable loop. In RPG Paper Maker, create a map, NPC dialogue, one quest condition, combat or interaction, and a save point.
Follow the RPG Paper Maker documentation for the version you install. Import a small set of custom assets, then change a dialogue branch and a quest requirement after the first playtest. Export to the intended target platform and verify save/load there, not only in the editor.
Compare alternatives on event scripting, asset licensing, localization, performance, and how easily another creator can maintain the project. A quick first room is useful, but the cost of building and revising the next ten rooms determines whether the engine fits.