How I learn GIS Development

Answer 1

http://www.gistutor.com
http://gisgeography.com/free-gis-programming-tutorials/

Answer 2

https://www.esri.com/training/catalog/57660ed7bb54adb30c9454a3/do-it-yourself-geo-apps/
I recently took and completed this ESRI course for Do-It-Yourself-Geo-Apps. It was an excellent introduction to GIS apps and GIS development. The course was free and gave a lot of freedom to explore the concepts and do as much (or little) work into GIS app development as students wanted. Below are more resources.
https://www.gislounge.com/learning-programming-for-gis/

http://monde-geospatial.com/category/gis/arcgis/

Answer 3

thanks for answering