Interim patches and 'installing' OPatch

[JMac]

So for the Opatch variable I'd call the Variable ... what? OPATCH?

And

now just go to the interim patch folder and type : opatch interim_patchnames

so there's no need to reference perl at all?

My perl install is at: C:\oracle\ora92\apache\perl\5.00503\bin\MSWin32-x86\perl5.00503 - Some docs I've read point you at specifying this pathname so that opatch knows where perl is and what version is used, is this not necessary?

Is it as simple as
(a) specifying OPATCH as a system variable - pathname to the Opatch executable from the zip file.
(b) possibly specifying ORACLE_HOME in a similar manner
(c) go to folder where the patch is and exeuting: opatch apply interim_patch_id ?