why i am not able to find external reservation?????????

HI @Ayush Jha 

I'm a member of the Trailhead Help team. Sorry for the inconvenience you are experiencing. 

Could you please use these steps to see the ExternalReservation. 

Click Data Model tab. 

Click ExternalReservation. 

Click Relationships tab.Ensure a relationship is there, if not, click Edit. 

Check the Show inactive relationships box. 

If an inactive ExternalReservation Contact ID appears, toggle the Active to On. 

If nothing appears, use the following information to add a new relationship: 

Field: Contact ID 

Cardinality: N:1 

Related Object: Individual 

Related Field: Individual Id 

Click Save & Close. 

Thank you!