1) Terrain of mountians or destroyed cities that reflect the image of you enemies homeworld would be a good start. Also a crater or shuttle wreck to indicate the Council crash would be good also.
2) The map may any size you wish with the Seer Council set up within 2" of the crash site and the crash site 5" from one edge of the map.
3) Then all other squads must be within 5" of eachother.
4) The same goes for the opposing army except that the crash site should instead be one of there squads.
Eldar - You get to move after your enemy since you arriaved late and just got prepared. You must hold of for six turns without losing your Seer Council. On the sixth turn you must roll a D6 at the end of your turn and the following turns. If you roll a 5+ your transport manages to land a lifts your Seer Council and surviving members to saftey. There is no retreat for your army for you must potect the Seer Council.
Opposing Army - You get to move first since you caught your enemy before the could prepare for battle. Your objective is to reach the Seer Council and capture them or kill them while also killing as many enemies as you can. You may not retreat or you will be shot for deserting your allies in battle.