How to restore a SQL server?

I have a couple of SQL servers and I´m doing restore test and I´m facing whit the problem that I have to do a two steps restores one for the OS whit the SDR and other for the SQL instance is that true or there is other way to do it in a one step?

I´m using a SQL Agent, Windows Agent, is an Appliance 3600.

Thanks for your help.