docker compose up -d --build
It will start 2 servers. One for the WordPress app and the other for the client part with SvelteKit.
localhost - WordPress
localhost:3000 - SvelteKit
Once that is done, go to localhost/wp-admin and follow the WordPress configuration instructions. Then, install and active the plugin named WPGraphQL.
Last step, go to WPGraphQL settings and check Enable GraphQL Debug Mod.
This plugin will allows your SvelteKit app to communicate with the WordPress app and get the data from it thanks to the Houdini GraphQL Client.