Need robocopy commmed with swtiches to compare and copy files

I have two folders on the server. Most files are the same  , but there are some files that are not the same. So, I have folder A-old and Folder-B new. I need to run robopy so if there any files that are in folder A-old that are not in folder B-new or if they are a newer modified date in folder A-old to be copied to folder B-new. This is on a 2012 server . Of curse skip all else. that is already there.

1. Copy files that are not in the destenation folder
2. Also copy files that  exist, but have a new modified date in the source folder ( A-old)