Update NAV - NAV 2017 CU9 --> CU10

Hello,

I need to understand how to update to the newest CU10 NAV 2017.
I have already tried once and failed. Therefore I need some professionnels to assist me.

I am currently working on 10.0.17972.0 (CU9), which is a demo company (Cronus) without any modifications.

Now I want to update to the latest CU10.

I have already read: https://support.microsoft.com/en-us/help/3204818.

1. Application:
To install the application files, follow these steps:
Unmodified databases:
Import the CUObjects.<Locale>.<Build No.>.fob file into an unmodified Microsoft Dynamics NAV 2017 database.
Replace the existing objects in the database with the cumulative update objects. After this it ask me to Sync. Schema for all tables.
Should I say yes to Synch here?

If I only import *.fob files during step 1, can I still run Dynamics NAV client or I am missing something here?
Purpose of only do step 1?

2. Platform:
What it is main purpose of updating platform. Are you not able to run Dynamics NAV Client without updating platform.

Thanks
Blackstone