How to sync iPad, iPhone and Mac for the first time

Necessary requirements to synchronise iDoceo between your devices (iPad, Mac, iPhone)

You will find all this options in the settings of your iPad/iPhone or Mac

Make sure to have the latest version of iDoceo available in the Apple App Store in all your devices.
Activate iCloud Drive in your iPhone and iPad settings and in your Mac system preferences.
For help: See the screenshot in the left.
Allow iDoceo to use iCloud in your devices settings.
For help: See screenshot in the right.
iphone white
Verify from the Settings > iCloud, of at least two devices, that there is enough free space in iCloud, more than 30% of total storage is recommended.
Corroborate that iPhone, iPad and Mac have an internet connection to be able to synchronise.
Confirm that you have the same Apple ID in all your devices, synchronisation will use your iCloud account of your Apple ID.
Activate iCloud Drive in the Settings of your iPhone, iPad and Mac
Allow iDoceo to use iCloud in the settings of your iPhone, iPad and Mac.
If you would like to synchronise iDoceo between devices, and this is the first time you download it and therefore do not have any data yet, go to:
Settings -> Synchronization -> Synchronise data across your devices.
Activate this option in all the devices you are going to use, iPhone, iPad and Mac, and do not do anything else.
Synchronisation is activated from this moment onwards and you should not touch any of this options again, it will work on its own.

How to activate the synchronisation

In the iPad or iPhone that contains your information.

Main menu -> Settings -> Synchronization -> Synchronize data across your devices.
See the screenshot for guidance.
The process to transfer your data to your personal iCloud has begun.
You will see a little wheel while the process is ongoing, just like in the image to the right. It will be either moving or static as well at times. It may change to a yellow check as well, it just means that it is synchronizing resources, but you still need to wait.
When the little wheel or yellow check changes to a green check and remains as a green check, it will mean that the process has ended and your devices are synchronized.

In the Mac

Main menu -> Settings -> Synchronization -> Synchronize data across your devices. Just as you see in the screenshot.
The synchronisation in the Mac can be activate at any moment after activating the iPad or iPhone synchronisation. When the green check appears in your Mac, and the iPad or iPhone also have a green check, that would mean your devices are synchronised and the synchronisation will work automatically from now on.
If instead you have all your data in your Mac and would like to synchronise with an iPad and/or iPhone, then you should do it the other way around. First turn on the synchronisation in your Mac and wait until the data transfer process ends, green check. Once it has, go to your iPad/iPhone and turn on the synchronisation there. When you see a green check here as well, the devices are synchronised and the synchronisation will work from now onwards.
The duration of the data transfer process will depend on the size for the information contained in iDoceo and also in the upload speed of Apple's iCloud.
It can take from several minutes to several hours.
The options used during the synchronisation set up, should not be ever used again in the future.
If we deactivate and activate again the synchronisation process, once the devices were already synchronising, the result of this new process will be uncertain and data can be lost.
Once devices are synchronised, all the work that is done in iDoceo Mac will be automatically transferred to iDoceo iPad and viceversa.
The only things needed are for both iDoceo apps to be open and with an internet connection.
If one of those devices, let's say the iPad, has been without internet when you were using iDoceo, it may take several minutes to transfer the iPad information to iCloud, once an internet connection is established.

What must NEVER be done to synchronise devices

Erase iDoceo app to download it again.
Try to synchronise devices using a a Backup made from one of them and restoring it in the other device
Deactivate and activate again the synchronisation button, doing this will make the synchronisation process endless.
Erase iDoceo's data directly from iCloud.
Log out and log in to your Apple ID or change it for another one.
Using iCloud - Tools, when not directed by iDoceo support.

Doing the first point will cause the loss of all your data in iDoceo, doing the second and third will block your iCloud temporarily due to excess of traffic or at least make it slower, the fourth, fifth and sixth points will cause unexpected errors and loss of data due to interfering with the process in iCloud directly.

Size of the file and resources to be synchronised with iDoceo

By defect, it will only synchronise resources of less than 15Mb. You can change this limit in your iPad/iPhone settings -> iDoce -> Resource size limit. 
You can do the same in your Mac by opening iDoceo -> Select iDoceo in the upper Menu of the Mac (next to the Apple icon) -> Reserved settings -> Maximun downloable file size.

How to send all the data in one class to iCloud

If by any reason the data in one class have not synchronise, even after the latest data in that class has synchronised already, you can force all information in that class to tranfer itself to iCloud, so it can be read by all the other devices. To do it use the Resync option.
It is very important that this options is only used from the device where the data is complete, not from the device where the data is missing. Also, it is not recommended to use this option regularly.