It can sometimes take a couple of minutes for iCloud sync for work. If it's not working after some time, firstly make sure that iCloud and iCloud Drive are enabled on both devices and Structured is enabled in the iCloud settings.
Secondly, check the iCloud Status in the app Settings and see Solving iCloud syncing issues if it's not syncing or fully synced.
As a last resort, you can try to open Structured on every device, keep the sync page open and wait about 10-15min, this should force your iCloud to sync.
