In Elven Architect, you have to manually create your city ... OR ... it gives an option to go to ElvenStats website as city planning tool has been linked to that site. Once in ElvenStats you can search for your city and as
MinervaOz stated go to view 'my city'. From that page is link to view your city back in Elven Architect so do not have to create it manually and/or can upload data from Elven Architect from ElvenStats website.
However the ElvenStats site only checks game status once a week. So if your city is newer then a week, ElvenStats will not find your city. From my experience, it actually took 3 - 4 weeks before ElvenStats found my city. So prior to that I just had to manually do my city, which as newer player / city, it was still small so not too hard.