Creating an Azure virtual network (VNet) with four subnets using the address space 192.148.30.0/26 several steps in the Azure portal. Below is a step-by-step guide with screenshots to help you through the process:

Step 1: Sign in to Azure Portal

Open your web browser and navigate to the Azure Portal.
Sign in with your Azure account credentials.

Step 2: Create a Resource Group (if needed)

If you do not already have a resource group where you want to create the virtual network, you can create one:

In the Azure portal, click on Resource groups in the left-hand menu.
Click + Add to create a new resource group.
Fill in the required details (Subscription, Resource group name, Region), and click Review + create and then Create.

Step 3: Create a Virtual Network

Now, let's create the virtual network with the specified address space and subnets:

In the Azure portal, click on Virtual networks from the home page, then click + Create.

Fill in the required details:
- Subscription: Choose your Azure subscription.
- Resource group: Select the resource group you created or want to use.
- Name: Enter a name for your virtual network.
- Region: Choose the Azure region where you want to deploy the virtual network.

IPv4 address space: Enter 192.148.30.0/26 for the address space.The image below shows that we can have 64 addresses within this network.

Step 4: Configure Subnets

Now, let's configure the four subnets within the virtual network:

Under Subnets, click + Add subnet.

Configure each subnet as follows:
- Subnet Name: Enter a name for the subnet (e.g., Subnet-1, Subnet-2, etc.).
Subnet Address range: Specify the subnet range within the virtual network address space (192.148.30.0/26). Ensure each subnet range is within the /26 address space (192.148.30.0 to 192.148.30.63)
Click Add for each subnet after configuring its details