I think I understand the notation but where do I put the two expressions on the BRU screen? I find that putting them in Repl. (3) "Replace/With" does not do it, i.e. nothing happens. For my simple example in my initial letter, I am using:
"(.+),\s(.+)" to be replaced by "\2 \1"
Note that the " are not used in the expression on the BRU screen but only shown here for clarity.