CAD structures and Feed techniques in HFSS

Hi

I want to draw cad structures of antennas especially the Bowtie and Trapezoidal Log periodic antennas. The ADK helps me to draw the basic/standard structure of the above. Now I want to introduce the slots and multilayered substrates and other materials like liquid crystals over it. When ever I try to change the structure there invokes a problem with the feed and porting.

Hence an exclusive tutorial on Drawing CAD strucutures and efficient usage of the tool in HFSS is needed. Please help me in this.