'No such module Firebase' exists

Hey guys. I've been building an app and have tried to implement Firebase for recording information provided from users and for push notifications. I have gone through the instructions for adding Firebase and during the process of adding the SDK frameworks I get a 'Failed to fetch Firebase-iOS-sdk' error. The package dependencies appear but I can't expand them, and Build Phases > Link Binary With Libraries and the following are linked;

• FirebaseCore.framework
• FirebaseFirestore.framework
• FirebaseMessaging.framework
• FirebaseAnalytics.framework
• FirebaseAuth.framework

I've edited my Package.swift file to include the SDK frameworks to relate to the packages they need to, but its still throwing up errors.

When the Build compiles, I get either the 'No such module exists' error, or 'Missing package product ***' error. It's starting to do my head in and I can't for the life of me work it out.

Any help would be greatly appreciated.