I think you use PADS flow, not Xpedition flow. If you look first page of link you sent, "Software Version EE 7.9.5" was seen. So this manual belongs to xPedition flow Constraint Editor System, not PADS. You can find manuals belong your tools clicking PADS Layout>Help>Documentation window> "Constraint Manager user's Manual". Or same document available in your Supportnet PADS Layout web page >Reference>Product Docs section as following link.
Constraint Manager User’s Manual (Software Version PADS VX.1.2) > Specifying General Clearance Rules:
If you are old PADS netlist flow user and now starting to use PADS Integrated flow, you can see match explanation between both flows rules system:
Netlist Project to Integrated Project Migration Guide > Rules Differences and Migration:
As you can read in that link, old copper to copper clearance is trace to trace clearance anymore. Old Board to Copper clearance is a general setting under Tools>options>Routing>General>Board Outline Standoff.
Netlis Flow Integrated Flow
Copper to [Trace | Via | Pad | SMD I Copper]
Trace to [Trace | Via | Pad | SMD | Trace] clearances are used.
Board to [Trace | Via | Pad | SMD I Copper]
This is a single global clearance in Options.
Hope it helps,