Hi,
You need to either know how to code and write a trading script that accesses said API (for example using Python or NodeJS), or find a trustworthy script that does it for you.
But why do you want to access the CEX.IO trading API only to write orders yourself? Usually trading APIs are used to automate at least part of that process.
Sorry what you mean there is a program or bot will make it?
sorry for my misunderstand
Let me put the question differently: Why do you want to use the trading API as opposed to simply using the CEX.IO website to place an order?