"%IF( ){ }" is a Dialog Processing Statement. It consist of two parts the "( )" part and the "{ }" part.
"( )" contain lua code that should result in a Type > Boolean. Either 0 or 1.
"{ }" contain a sequence of text, separated by "::".
If only one text part exists then false will just remove the Statement.
There can be more then two text parts, but only the first two can be chosen.
The whole "%IF( ){ }" is replaced by either the first text part, if the boolean is true, or the second part, if the boolean is false.
So "%IF(0){Hello::Hey::Hi}" is replaced by "Hey".