I assume you mean the part that says "set trigger or direct trigger". I don't own a Steyr-Mannlicher, but will hazard a guess that this refers to a single-set trigger similar to the one on my CZ.
What that means, in English, is that in one mode it operates just like a normal trigger with a light to moderate pull weight. When operated in "set" mode, the pull weight is much lighter, often less than 1 pound.
Sooner or later, somebody who actually owns a Steyr-Mannlicher will probably come by with the correct info.
Edited to add: By the way, that is one pretty rifle.