https://skip.tools/docs/deployment/ should say that for your first time uploading an app to App Store Connect, your best bet is almost certainly to use Xcode's Archive feature.
Then, when you want to automate that, you can set up fastlane. https://docs.fastlane.tools/actions/upload_to_app_store/ is very difficult for a newbie to understand if you've never uploaded a build by hand at least once.
https://skip.tools/docs/deployment/ should say that for your first time uploading an app to App Store Connect, your best bet is almost certainly to use Xcode's Archive feature.
Then, when you want to automate that, you can set up fastlane. https://docs.fastlane.tools/actions/upload_to_app_store/ is very difficult for a newbie to understand if you've never uploaded a build by hand at least once.