15. Glue on the head of your choice.
16. Mix some greenstuff, and put a roughly triangular patch like this on your finger (wet your finger first - helps keep it from sticking). This is for the cape that goes over the shoulder pads.
17. Place it over the shoulder pad, stretching it as necessary. You may find that your piece wasn't big enough - either take it off and start again with more, or (as I did) add some where you are missing coverage.
18. Repeat for the other shoulder.
19. Use your tool to smooth the grrenstuffed cloak and put natural grooves in it. Pay particular attention to where it joins the caps and the bottom - you want the transition to be as smooth as possible - you may need to reach under his shoulder in the front and push the greenstuff back some. You may also need to rebuild some detail on his cape - here, I still need to redo the rope on the skull, which got sawed off with the shoulder.
20. Put the miniature aside to let the cape cure.
21. Now we rebuild the fur trim on the cloak. Roll a thin sausage of greenstuff and place it across the shoulder next to the shoulder protector. Put it in place and trim it if it is too long. This is easiest done with your greenstuff tool.
22. Use your tool to flatten it and put grooves in it to mimic the fur trim that remains on the cloak. You may find that you don't have as much coverage as you would like (or too much) - remove or add greenstuff as and where needed.
23. Repeat on the other side. Be careful not to accidentally press on the other shoulder - if you do, be prepared to redo your work there.
24. Put a blob of greenstuff on the back pack, then squish into the position you want on the back. After you do so, see if any greenstuff for the backpack is visible - if it is, either trim it (if it isn't structural), or sculpt it into fur.
25. FInd something to do with the leftover legs - something I have yet to figure out.
Oh, as a note, if you don't like the fantasy torsos, you can (with some trimming of the sides and the warrior's torso) use a chaos space marine front instead. This does mean, however, you don't get the neck guards, which I think look pretty cool. As well, most of the torso is hidden by the weapon, so it doesn't look overly "fantasy" anyway.
Anyway, hope that was informative.