Hi Asad,
Did you check out the learning paths of the academy? They are very valuable resources to get up to speed quickly.
This learning path deals with consuming data from a REST service:
https://academy.mendix.com/link/paths/44/Importing-and-Exporting-Your-Data
Other possible resources: https://www.mendix.com/videos/consuming-rest-services-with-mendix/
or https://docs.mendix.com/refguide/integration/consume-a-rest-service/
I hope this helps.
Michiel