The main body...was interesting...mostly a box shape again, but with a twist...
This one I did tabs on the top piece and along the bottom edge of the sides. The edges of the top piece, it seemed like they were meant to bend down slightly and come together in those corners (see first picture).
Around where the engines would go, I left tabs, then cut them a whole lot so it would better accommodate the contour of the engines.
The sides just wrap around, probably good to start at the front and work back! As this works around, you'll have to bend and adjust the top piece to match the ups and downs going on the sides.
As for the bottom piece, I left that off until the very end of the build. It was really helpful to have that open when it came to attaching the wings/tail fins/cockpit/engines on the main body....ESPECIALLY, the engines!!! (Didn't do that last time, ended up with a couple stylus shaped "exhaust ports" because I closed up the main body too soon
)
...And that just leaves the engines and final assembly to take care of... later
edit: ...oh...just realized I probably could have incorporated that cockpit chrisstahl designed! Oh well...since he said he was going to build this, I'll leave it up to him