You can work with the bridge in automatic mode or call each action yourself (step-by-step mode)
1,2 items - Common for both modes
Recommended for most cases (you don't need to dive into bridge design to use it)
4-6. Step by step mode - recommended for developers who know bridge desin and want more control when interacting with the bridge
https://github.com/harmony-one/docs-home/blob/master/developers/learn/tutorials/bridge-sdk-other.md