Hello！
The speaker of the blog is NeYhaaa (｀∀´)
This time I will talk about iCloud backup 
・You will be backing up in a Wi-Fi environment.
・Please check the amount of data used on that mobile.
Apple offers free storage up to 5 GB.
If the data capacity exceeds 5 GB, purchase storage capacity or organize the data.
Start Backup 
setting 
iCloud Backup Create backup now
※ Normally, mobile device backup is on. If the backup is completed automatically, the latest update date and time is displayed.
If there is too much data it will take time to complete the backup.
Let's do it when you do not use sleeping hours or mobile.
Please contact us whenever you do not know how to back up or when you are worried doing it. 
Thank you for happyfield always.