Hi Meghana,
Welcome to outsystems community.
This questions are already answered on the forum but as you are new, do search questions in forum before posting any new queries.
To start with you can go through below guided paths
https://www.outsystems.com/training/paths/1/becoming-a-mobile-developer/
It has good examples in exercises and once you complete the tutorial, you can definitely build an app. Please go through it and let me know if you face any issues
Also you can go through reactive web course if you are interested
https://www.outsystems.com/learn/paths/18/becoming-a-reactive-web-developer/
Regards,
Swapnil