how do i restore my new iphone

I lost my phone the other day and i've been sent a new one to replace it. My old iphone was backed up on the icloud and i can see that the back up is there on all of my other apple devices. When i was setting up the replacement iphone, there was an option to restore the iphone using a previous back up, however, the software on the new iphone needed to be updated. I skipped the steps and just went straight to the home screen and updated the software but now I dont know how to restore the replacement iphone with my old phones data using the icloud.