How to connect to Local Server - Mobile App White Labelling

Hi guys,

I am following this link to do the White Labelling:

I encountered 2 issues:

(1.)
In this page, there is no mention about how to configure the Rocket Server ROOT_URL. How am I configure to make this Mobile App to talk to my test server?

(2.)
I have built errors:

** BUILD FAILED **

The following build commands failed:
ValidateEmbeddedBinary /Users/christan/Library/Developer/Xcode/DerivedData/RocketChatRN-gbsjedfydysoqncxnhisrmnffatq/Build/Products/Debug-iphonesimulator/Rocket.Chat\ Experimental.app/PlugIns/ShareRocketChatRN.appex
ValidateEmbeddedBinary /Users/christan/Library/Developer/Xcode/DerivedData/RocketChatRN-gbsjedfydysoqncxnhisrmnffatq/Build/Products/Debug-iphonesimulator/Rocket.Chat\ Experimental.app/PlugIns/NotificationService.appex
(2 failures)

Anyone know, what are the 2 failures about? any advice?

Appreciate your help.

Thanks.