Either it was, despite it's looks, simple, or you are loving amazing. Most likely the latter.
It came with an instruction manual. Just follow the instructions.
It was really complex though, I messed up a few times on the legs.
Also, did anyone else think the Rahkshi weren't really that great? They just seemed too simple and bare-bones.
They were awesome for their time. They dwarfed the Toa Nuva in size, thanks to their new knee joints, and the skeletal look was obviously intended. Then came Metru Nui, and all the ordinary Toa (Vahki too) had knee joints, and the Rahkshi's charm was lost. Especially since the Vahki were functionally identical to the Rahkshi (spin a gear on the back, they swing their arms side to side). I'd still take a Rahkshi over any of the later action figures though.