In the example you listed , INPUT is the actual file named in the program. The to file attribute would be the LIBRARY/NEWFILE and MBR is the member of that new file.
We use this for setting up things like our FTP process
OVRDBF FILE(INPUT) TOFILE(MYSRC022/QCLSRC) MBR(FTPOHIO)
For more info on the command read the IBM documentation here