Hi Dreato,
I am not sure if I understood you correctly. I believe you have create a steel model and need to create an isometric drawing?
In ASD Steel module. start the group command[Groups panel]. Select all the steel objects you need and press ENTER. Input the name for this group and ENTER. If you did this correctly. In object Inspector, Position Tab you will see the group listed with same name. Select it & right Click and select Attach Documents. You get a new dialog box allowing you to select type of drawings. here you have various options for isometric drawing position and scale.
If you were askin to create a 3D model steel structure, then you need to use commands like workframe, profile, plates, connections, etc...
read the getting started guide that can be downloaded from Autodesk website: http://usa.autodesk.com/adsk/servlet/index?siteID=123112&id=13111928
Hope this is helpful.
Regards,
NEIL