@reez have you looked at the other threads in this forum? a bunch of people have found different solutions to their problems: Playground misbehaving (Chapter 3) - #10 by icanzilb (100+ posts) and Realm - Building Modern Swift Apps : Script Error - #10 by icanzilb (100+ posts)
Regardless, since plenty of people used to have difficulties we’re releasing a different version of the code that doesn’t use CocoaPods for playgrounds - we’re preparing a book update right now