In this tutorial there is a Step By Step that explain how to start to develop a new program on STM8S.
In general I suggest this kit:
- STM8 IDE include: ST Visual Develop (STVD) + ST Visual Programmer (STVP)
- STM8 Library
- Cosmic C Compiler for STM8 that is free and is here
The demo is based on:
STM8S-Discovery + STVD/STVP + Cosmic C Compiler