Explanation
You can create and manage resources in the following ways:
Oracle Cloud Infrastructure ConsoleThe Console is an intuitive, graphical interface that lets you create and manage your instances, cloud networks, and storage volumes, as well as your users and permissions.
See Using the Console.
Oracle Cloud Infrastructure APIsThe Oracle Cloud Infrastructure APIs are typical REST APIs that use HTTPS requests and responses. See API Requests.
SDKsSeveral Software Development Kits are available for easy integration with the Oracle Cloud Infrastructure APIs, including SDKs for Java, Ruby, and Python. For more information, see Developer Resources.
Command Line Interface (CLI)You can use a command line interface with some services. For more information, see Developer Resources.
TerraformOracle supports Terraform. Terraform is "infrastructure-as-code" software that allows you to define your infrastructure resources in files that you can persist, version, and share. For more information, see Getting Started with the Terraform Provider.
AnsibleOracle supports the use of Ansible for cloud infrastructure provisioning, orchestration, and configuration management. Ansible allows you to automate configuring and provisioning your cloud infrastructure, deploying and updating software assets, and orchestrating your complex operational processes.
For more information, see Getting Started with Ansible for Oracle Cloud Infrastructure.
Resource ManagerResource Manager is an Oracle Cloud Infrastructure service that allows you to automate the process of provisioning your Oracle Cloud Infrastructure resources. It helps you install, configure, and manage resources using the "infrastructure-as-code" model. For more information, see Overview of Resource Manager.

Explanation
When you work with Oracle Cloud Infrastructure, one of the first steps is to set up a virtual cloud network (VCN) for your cloud resources.
VIRTUAL CLOUD NETWORK (VCN) :
A virtual, private network that you set up in Oracle data centers. It closely resembles a traditional network, with firewall rules and specific types of communication gateways that you can choose to use. A VCN resides in a single Oracle Cloud Infrastructure region and covers a single, contiguous IPv4 CIDR block of your choice. See Allowed VCN Size and Address Ranges. The terms virtual cloud network, VCN, and cloud network are used interchangeably in this documentation. For more information, see VCNs and Subnets.
SUBNETS :
Subdivisions you define in a VCN (for example, 10.0.0.0/24 and 10.0.1.0/24). Subnets contain virtual network interface cards (VNICs), which attach to instances. Each subnet consists of a contiguous range of IP addresses that do not overlap with other subnets in the VCN. You can designate a subnet to exist either in a single availability domainavailability domain or across an entire region (regional subnets are recommended). Subnets act as a unit of configuration within the VCN: All VNICs in a given subnet use the same route table, security lists, and DHCP options (see the definitions that follow). You can designate a subnet as either public or private when you create it. Private means VNICs in the subnet can't have public IP addresses. Public means VNICs in the subnet can have public IP addresses at your discretion. See Access to the Internet.

Explanation
https://blogs.oracle.com/cloud-infrastructure/innovation-in-edge-services-the-oracle-cloud-infrastructure-edge-ne