Hello Mustafa,
I suggest to check the Sample1 screen implementation:
- WebBlock GoogleMaps\Map has an event called MapInitialized
- Evaluate the implementation of that client-action
- As you notice this is the place we fetch the data about our locations
- After that, we also assign to the client-variable MarkerData
- The client-variable MarkerData is used in the WebBlock as an input parameter
Please bear in mind this is just an approach from most common use-cases, you can take different implementation approaches. I strongly suggest to do a simple exercise and try to re-create the Sample1 screen in a different application so you may understand the logic and how it is built
Cheers