Move roadmap files and contribution instructions

README.md

@@ -46,7 +46,7 @@ If you think any of the roadmaps can be improved, please do open a PR with any u
 
 ## 👬 Contribution
 
-The roadmaps are built using [Balsamiq](https://balsamiq.com/products/mockups/). Project file can be found at `/ROADMAPS.bmpr`, open it in balsamiq, do the necessary modifications, export the diagrams as PNG files, put them in the Readme at relevant places and create a PR.
+The roadmaps are built using [Balsamiq](https://balsamiq.com/products/mockups/). Project file can be found at `/project-files` directory. To modify any of the roadmaps, open Balsamiq, click **project > import > Mokup JSON**, it will open the roadmap for you, update it, upload and update the images in readme and create a PR.
 
 - Open pull request with improvements
 - Discuss ideas in issues