shit uhh.. there actually pretty long. 4 or 5 pages. but i'll do a summary for you. hope this is legal as far as forum rules go... if not sorry!
1. choose forces
agree on points limit
your army can include: usual 40k army, usual 40k army with spearheads or just spearheads (no limit on how many other than the fact that you can't take more than 1 spearhead of each type)
2. prepare the battlefield
basically use the 'organising a battle' section of the main rule book with the exception that both players deploy on the narrow edges of a 6x4 table. outflanking units arrive on the long edges. slightly less, and more clumped up, cover than usual.
3. select a mission
normal game lenth. scoring units are troops tanks and walkers (even damaged or immobilised, not destroyed) and all spearhead units. swarms never count as scoring.
missions: breakthrough 1 victory point for each unit even partially with the enemy's half of the table and the other two are way too lenthy and complicated to write in this post
deployment rules are also really long too sorry!
anyway that's a quick summary and all i can give as i think even that much is against forum rules, not sure though....