Add android playstore link, ios appstore link, one word scheme and Host name. (Note: after release apps in appstore and playstore don't forgot to add your link in admin panel)
2. For android go to android > app > src > main > AndroidManifest.xml and change scheme and your DomainName here
3. For ios go to ios > Runner > Info.plist and change scheme
4. Change your DomainName in lib > helper > Constant.dart.