Netweaver 7.31 Kernel Update

Hi Guys

I have kernel 7.20 with NW 7.31 on WIN 2012 and want to update to 7.20 EXT.

I need quick guide to do the update without using SUM if possible.

I downloaded SAPEXEDB_402-20006745.SAR from SSMP (is this the only file I require).

I wanted follow procedure whereby I copy files to usr\sap\sid\sys\exe,

however I don't have an exe folder  - only JVM and UC folders and the contents of sapexedb is much less than the existing exe folder.

Please advise.

Joe