Hello, if you are trying to use OWL in a standard JavaScript project I would recommend one of these two starter template repositories:
https://github.com/Coding-Dodo/OWL-JavaScript-Project-Starter (Rollup.js, OWL, Livereload, Jest)
https://github.com/Coding-Dodo/OWL-JavaScript-Tailwind-Project-Starter (Rollup.js, Tailwind, OWL, Livereload, Jest)
And if you want a full tutorial on creating an App with OWL you can take a look at this article series, it may interest you:
https://codingdodo.com/realworld-app-with-owl-odoo-web-library-part-1/ (Use of starter template, general knowledge, Components architecture, and Routing)
https://codingdodo.com/realworld-app-with-owl-odoo-web-library-part-2/ (OWL Store for State managements, authentication, Routing guards, APIRequests)
https://codingdodo.com/realworld-app-with-owl-odoo-web-library-part-3/ (Dynamic Routing, async components functions willUpdate and willUpdateProps).