Hi Henrique,
The Styles and Layers have got a new look since IronCAD 8 PU1. In IronCAD 8 and earlier the settings were separated and sometimes hard to find because they could be very "deep down". Now everything should be found under the Styles and Layers button on the left side. You also have a option for Line Types which are used in different Styles.
1.
Line Types: A list of the existing line types, thin, thick, dotted etc.
2.
Styles: Controls the settings for all the elements in the drawing ie views, dimensions etc.
Layers: Controls visibility, if a layer is locked and what color it may use.
I don't know if there's any short demo film or something that shows how it works nowadays?