you’ve run into a fairly common misconception:
Your local Foundry Application and The Forge are not linked in any way
Here’s the guide for importing your local content into the Forge: Importing Worlds/Modules/Systems - W/ Video Tutorial
Local FoundryVTT App is:
NodeJS Server
Chromium Browser which connects to it
(you can connect to the local app by launching the app, minimizing, then going to http://localhost:30000/ in your browser)
Forge is:
FoundryVTT NodeJS server
You connect via browser