To get started with a new bitcoin exchange, there are two ways to go about. The first one is building the exchange from scratch. This process involves a few mandatory steps such as,

Determining the operational location of your exchange and obtaining a license.
Complying with other regulatory norms and KYC norms based on your geographical area.
Partnering with a bank or a payment processor
Boosting liquidity for the exchange by connecting with external exchanges
Implementing advanced technology and security for the exchange
Constant Maintenance, and customer support

These are the key steps involved with building an exchange from the ground up. If you are looking to get your exchange up and running within a short turnaround time, the alternative option would be to acquire a white label bitcoin exchange.

The difference with a white label exchange is that it is ready-made with every feature and functionality required for the exchange to run smoothly. The development part is already taken care of, while you can concentrate on customization according to your personal preferences and further enhancement of your exchange. This will help with a quick launch saving you some time invested in development.