For you to get start with NEO Smart Contract you must set your enviroment first.
You can choose one of the languages aviable on the community and start code. The languages available is listed below:
- C#
- Java
- Python
- Go
- etc ( some languages stills in development and tests )
The most used languages to create Smart Contract inside NEO Blockchain is C# and Python, so i'm gonna talk about them.
You can see below the official tutorial guide to set up your enviroment:
Official instalation guide - C# for Windowns
Official instalation guide - C# for MacOS
Official instalation guide - C# for Linux