A THREAD FOR NEWCOMERS!

I would like to know about composite artifacts, such as the Alliance of Angels, the Cloak of the Lich King, the Titan's Sword, and others. What do you need to do to combine several artifacts into one large artifact? Also, I'm interested in this: Does mixing creatures that "hate" each other in one army pose any problems? (Djinn - Efreet, Angels - Devils, etc.)