This is a very basic overview of syncing data between Informant and a sync service.

First, before you can sync your data, you will need to determine where your data resides.
Please open the native or "stock calendar"  and your Reminders Applications and see if your Informant data is visible there.

If it is,  that means that your Informant is configured to use the iOS calendar and reminders database.  When configured this way none of the data is actually stored in Informant, rather the device is simply sharing its database with Informant.  This also means that the device itself and not Informant is responsible for syncing the data.  The data will be synced based of the settings of your device itself.

If you cannot see your Informant data in the device's stock calendar and reminders apps this means that your data is in the Informant database and it can be synced via the supported Informant sync services.

The supported sync services are as follows:

Google Calendar        Free         Calendar Events Syncing

Google Tasks             Free         Basic Task Syncing

Toodledo                    Free/Paid Task and Notes Syncing

Informant Sync          Paid          Syncs all Informant Elements

Once you have decided what sync service to use you will need to go online and create an account for the chosen service(s) if you haven't already.

Then go into the Informant app settings> sync accounts> and tap the add button to add the account of the service you wish to sync with using the credentials you created online for that particular service.

Once you login, tap the begin sync button.  Once the sync is completed on one device then you can go to the next device and sync it the same way.

As long as your data is verified to be in Informant and not just being read from the iOS by Informant, confirm that you are logged into the same Informant Sync account across all devices you wish to Sync with.

This can be checked by going into Informant Settings>Accounts>Informant Sync. Here, you will see your Informant Sync username, your expiration date, and the most recent sync date. This information needs to match across all devices.

This is all you'll need to do to begin Syncing with Informant Sync.