How to make this?(given in the link)....https://d2t1xqejof9utc.cloudfront.net/pictures/files/10546/large.jpg?1332899233
The design is simple...
If you will create more extrudes whit only one sketch, you must create outputs in your sketch. The best way to do that on this picture is to draw one vertical line and two horizontal lines on the ends of the vertical line, like as a I-profile.
Create in the sketch outputs from all 3 lines in your sketch, the function for that is in the sketch module "output featchure". So now can you use every line from the sketch individually.