INF files for multiple OS's

Question

I am trying to edit an INF file for a cypress controller to include more information for 64 bit OS as well a 32 bit. The current INF file is as follows which is only for 32bit, I want to edit it to work for a 64 bit Win7 OS as well.

[DestinationDirs]
USB.Files.Ext = 10,System32\Drivers ;10 = Windows Directory

[USB.Dev]
CopyFiles=USB.Files.Ext
AddReg=USB.AddReg

[USB.Dev.HW]
AddReg=USB.AddReg.Guid

[USB.Dev.NT]
CopyFiles=USB.Files.Ext
AddReg=USB.AddReg

[USB.Dev.NT.HW]
AddReg=USB.AddReg.Guid

[USB.Dev.NT.Services]
Addservice = USB, 0x00000002, USB.AddService

[USB.AddService]
DisplayName    = %USB.SvcDesc%
ServiceType    = 1                  ; SERVICE_KERNEL_DRIVER
StartType      = 3                  ; SERVICE_DEMAND_START
ErrorControl   = 1                  ; SERVICE_ERROR_NORMAL
ServiceBinary  = %10%\System32\Drivers\USB.sys
LoadOrderGroup = Base

[USB.AddReg]
HKR,,DevLoader,,*ntkern
HKR,,NTMPDriver,,USB.sys

[USB.Files.Ext]
USB.sys

[USB.AddReg.Guid]
;HKR,,DriverGUID,,%USB.GUID%

I am totally new with INF files what does [USB.Dev], [USB.Dev.NT], etc mean? And how do I edit this INF to include 64bit Win7 OS as well. Please guide me through.