How to restore jira software from backup

[Serhii Kholin]

Hi, 
every week, I create a backup of my JIRA-cloud software systems and Confluence. 

I have two questions:

1. Before Atlassian got a problem with backup, the backup file of all JIRA was almost 50Gb. Now a backup, that I am creating, has amount 17Gb. Why backup now is smaller?
2. How can I restore my JIRA from my zip backup file? How can I check it, where I can restore my file for the test?

[Nic Brough -Adaptavist-]

We don't know what changed the size of the backup.

To restore it, you need to build another JIRA and Confluence system, of the highest available version, and import the files into them.  Or buy another Cloud account and upload them there.