Floor assembly worked very similarly to that of the base except that the floor did not have numbers to label the male/female pegs like the base did. To help figure out the location of where everything goes I used the base to place the floors upon as some pieces fit really snugly and help show the orientation.
Using the stair indent, look for the three wholes on the base or its the front orientation of all base pictures. The first piece is FH_ExtFloor_A which has two dock pillars but no rope go right at the top o the stairs. This will fit around the rockface on the lefthand side. Then following counter-clockwise the rest of the floors ExtFloor_B, ExtFloor_C, and ExtFloor_D are placed. ExtFloor_D will also fit snugly to the rocks in the back. If you continue to have issues look at the picture below as all the slots are labeled on how they go.
Once all pieces are labeled as to where they go. I glued all exterior pieces and interior pieces separately. Once glued I connected the interior with the exterior. This was due to the interior not having much support for IntFloor_B in the corners and allowed for the entire interior floor to be supported more easily. DO NOTE GLUE FLOORS TO BASE YET! I glued the pieces separately from the base to allow the stairs to be added later which go under the floor from the base as well as allow ease in painting.
Slideshow of Assembled Floor shown below: