well, ok no problem

then... just use the way i said

open macro / new macro
to record all what you will do

add a scenario the usual way (don't care wich one)

stop the recording of the macro recording

and then go in the VBA macro editor
you'll see a command like
ActiveSheet.Scenarios.Add etc.

here you see the syntax (how to add a scenario in vba)


then ... the question is: do you really know how to write a macro ?
maybe you do not just need one syntax. Tell us your level,
and also , please, try to "try said things".