in auth-sample/src/main/java/com/spotify/sdk/android/authentication/sample/MainActivity.java [118:124]
private AuthorizationRequest getAuthenticationRequest(AuthorizationResponse.Type type) {
return new AuthorizationRequest.Builder(CLIENT_ID, type, getRedirectUri().toString())
.setShowDialog(false)
.setScopes(new String[]{"user-read-email"})
.setCampaign("your-campaign-token")
.build();
}