Hi Ather,
Mendix has updated their Scrum support with a new tool Epics. https://docs.mendix.com/developerportal/collaborate/epics/
https://epics.mendix.com/index.html if you need the “older” tool, goto https://sprintr.home.mendix.com/link/myapps and open your App. Go to Stories to work with User stories.
Go Make It