How to properly delete archived reuqests in Support Center Plus

Hello,

could you please help me in understanding in how to properly delete archived requests in Support Center Plus?

We are using Support Center Plus 7.9.0 Build Number 7942 and MSSQL DB

i found the following article in knowledge base, but i'm not totally sure about results after this query executing

which variables i need to change in query below? only dates?

delete from workorder where dateadd(s,datediff(s,GETUTCDATE() ,getdate()) + (CREATEDTIME/1000),'1970-01-01 00:00:00') <= convert(varchar,'2010-04-01 00:00',21)

also i want to understand which folders (from here C:\ManageEngine\SupportCenter\fileAttachments) i can clean up (i suppose manually) after executing proper delete query from MSSQL server?

thank you