npm install
npm run start
And then go to localhost:1234
If you need to change things such as navbar for example, you will find all the reusable component througout the pages in the folder : /src/partials.
Change the html here and modifiy the css in the good file in /src/scss.
That is almost everything you need to know.
If you have run : npm run start, parcels has an excellent hot reload except if you are on another page than index.html. There is a bug with parcels that requires you to manually refresh the page when you are not working on index.html.