SSRS in integrated mode

Hello experts,

 

I have 2 servers, Server  X with sharepoint appl 2016 installed , and server Y where it is sharepoint sql 2016 database.

I also had a third server Z where it was before the SSRS in the integrated mode. This third server is down and I need to install it from scratch. I installed the SQL instance and add-on feature of sharepoint in this server Z.

The configuration on central admin were already made before - SSRS service is created /started and Service application too, proxy as well are already configured in central admin. 

I tried to edit the SQL Server Services Service Appl , and it was succesfull, but the 3 databases are not created... 

pls help  how can I go on with this situation, why are not the 3 databases created ..