Let's create two subnets under the chap7 VPC (network) by following these steps:

1. In order to create a subnet, you have to choose the region. By typing gcloud compute regions list you will know which regions are available to you:

2. Let's choose us-central1 and us-east1 to create two subnets under the chap7 VPC with the following configuration:

$ gcloud compute networks subnets create chap7-us-central1 --network=chap7 --range=192.168.1.0/24 --region us-central1

$ gcloud compute networks subnets create chap7-us-east1 --network=chap7 --range=192.168.2.0/24 --region us-east1

3. Check the following command to see whether subnets are configured properly or not:

$ gcloud compute networks subnets list --network=chap7
NAME               REGION       NETWORK  RANGE
chap7-us-east1     us-east1     chap7    192.168.2.0/24
chap7-us-central1  us-central1  chap7    192.168.1.0/24