in this case, you need to make sure that you have loaded all of the default libraries. the detail markers are library parts that need to be loaded into archicad to enable it's function.
you should be able to key in your text/marker reference in the 'parameters' list of the detail marker when you have it loaded and selected...
b e n f r o s t
b f [a t ] p l a n b a r c h i t e c t u r e [d o t] n z
archicad | sketchup! | coffeecup