From scenario: Deploy Azure Firewall to VNetwork1 in Sub2.
Azure firewall needs a dedicated subnet named AzureFirewallSubnet.
Reference:
https://docs.microsoft.com/en-us/azure/firewall/tutorial-firewall-deploy-portal
Topic 3, Fabrikam inc
General Overview
Fabrikam, Inc. is a consulting company that has a main office in Montreal and branch offices in Seattle and New York. Fabrikam has IT, human resources (HR), and finance departments.
Existing Environment
Network Environment
Fabrikam has a Microsoft 365 subscription and an Azure subscription named subscription1.
The network contains an on-premises Active Directory domain named Fabrikam.com. The domain contains two organizational units (OUs) named OU1 and OU2. Azure AD Connect cloud sync syncs only OU1.
The Azure resources hierarchy is shown in the following exhibit.

The Azure Active Directory (Azure AD) tenant contains the users shown in the following table.

Azure AD contains the resources shown in the following table.

Subscription1 Resources
Subscription1 contains the virtual networks shown in the following table.

Subscription1 contains the network security groups (NSGs) shown in the following table.

Subscription1 contains the virtual machines shown in the following table.

Subscription1 contains the Azure key vaults shown in the following table.

Subscription1 contains a storage account named storage1 in the West US Azure region.
Planned Changes and Requirements
Planned Changes
Fabrikam plans to implement the following changes:
Create two application security groups as shown in the following table.

Associate the network interface of VM1 to ASG1.
Deploy SecPol1 by using Azure Security Center.
Deploy a third-party app named App1. A version of App1 exists for all available operating systems.
Create a resource group named RG2.
Sync OU2 to Azure AD.
Add User1 to Group1.
Technical Requirements
Fabrikam identifies the following technical requirements:
The finance department users must reauthenticate after three hours when they access SharePoint Online.
Storage1 must be encrypted by using customer-managed keys and automatic key rotation.
From Sentinel1, you must ensure that the following notebooks can be launched:
Entity Explorer - Account
Entity Explorer - Windows Host
Guided Investigation Process Alerts
VM1, VM2, and VM3 must be encrypted by using Azure Disk Encryption.
Just in time (JIT) VM access for VM1, VM2, and VM3 must be enabled.
App1 must use a secure connection string stored in KeyVault1.
KeyVault1 traffic must NOT travel over the internet.

Reference:
https://docs.microsoft.com/en-us/azure/virtual-network/manage-network-security-group

https://docs.microsoft.com/en-us/azure/firewall/tutorial-firewall-dnat

https://docs.microsoft.com/en-us/azure/active-directory/hybrid/choose-ad-authn

Reference:
https://docs.microsoft.com/en-us/azure/azure-arc/servers/agent-overview
https://docs.microsoft.com/en-us/azure/security-center/deploy-vulnerability-assessment-vm