What is LB, RB & ORD in correlation?

‘LB’ is left boundary. We normally take few words left to the value which we want to correlate and will be assigned to LB. And few words right to the value will be assigned to RB. Since every time when we run the script, the correlated value will change by the server but not left and right side values. So, when correlation is done, the server recognizes the correlation value by reading the LB & RB values. ORD is ordinance. i.e. the occurrence of the correlated value in the entire script, when it changes in the 1st occurrence or 2nd, 3rd etc..Depending on this we keep ORD =1, ORD=2 etc..If we are not sure of which occurrence then we put ORD = ALL.