VMS Help DSR, DSR Commands, .HEADER LEVEL, Parameters  *Conan The Librarian (sorry for the slow response - running on an old VAX)

 n

    A number from 1 to 6 that specifies the level of the header. Do
    not confuse the level numbers with the header numbers that are
    printed in your document just to the left of the header title.

 +n

    Adds n to the current header level number.

 -n

    Subtracts n from the current header level number.

 title

    The name of the section you are now starting. Do not precede the
    title with a semicolon (;).