Solution

The first step is to assemble the puzzle pieces into a solved 10 by 5 structure. The second step is to figure out that each piece corresponds to a single letter, using the Puzzle Code. Translating the pieces gives you the information that the string revealed by the solved puzzle is encoded using a keyed Vigenère and that the key is abandonments. Decoding the string gives you the xxxdiscombobulatexxx. Once you remove the padding, you get the word discombobulate.