Becoming an Internet Service Provider (ISP) is not an easy task. The biggest obstacle to becoming an ISP is the large amount of capital required for the equipment and building needed. Network bandwidth, cooling and power are all resources that have to be planned.
Find a suitable building to house the ISP's data centre. Ideally, the building should have raised floors to route cables.
Purchase and install UPS units, a diesel power generator and HVAC units. The UPS and diesel power generators are needed when city power is interrupted by a power outage. The HVAC units are needed to keep the data centre cool, because the equipment running the ISPs generates heat which can damage equipment.
Enter into a peering arrangement with one or two upstream Internet providers. Your ISP has to have its own connection(s) to the Internet via peering arrangements.
Buy high-speed fibre optic lines from the local telecommunications utility to connect to the upstream Internet provider(s).
Purchase, install and configure enterprise-grade routers, switches and computers. Do not go the cheap route on the equipment or the customers will complain early and often about your ISP's slow performance. All this equipment forms the backbone of the ISP's network.
If the ISP is selling Internet DSL connectivity to consumers, set up a customer installation process whereby customer orders for service are routed to the local telecommunications utility for connection over the telephone system.
If the ISP is selling web-hosting services, configure the computers to run as a virtual private server (VPS) so that customers can host their own websites in their own virtual instance at the data centre.
Make sure there is an adequate amount of every resource, especially related to network bandwidth, cooling and power. If resources fall short, there will be complaints from the customers.