This three storey tower is typical of an AngloSaxon "Keep". It's deliberately constructed with a strong stone base with an outside staircase leading to the only entrance. In times of seige, they would set fire to the staircase in order to make it harder for the enemy to reach the door - and virtually impossible for them to use a battering ram to open it.
First locate the four stone walls and the stone floor for the "basement". The floor has a trapdoor in it which might lead down into an underground room inside the "Motte".
Be especially observant about the four wall parts - notice the small tab on the bottom-left corner of each one in the photograph - in all Renaissance Miniatures models, that tab should be at the bottom-left when you assemble the building.
Glue together the four walls and the floor:
Repeat the process for the next floor up - this floor has narrow windows to make it harder for beseigers to climb in.
It's a good idea to fit each new room on top of the one below (DO NOT GLUE THEM TOGETHER!!!) to be sure you'll have a good fit after the glue sets:
Onward and upward! This floor would be the living quarters for the owner of the tower - it has wider windows and they are on all four sides so they can easily spot potential attackers.
There is also a staircase that leads up from the lower floor:
Finally, we have reached the roof and battlements:
Remove the top floor once the glue has set and glue the crenellations around it:
Locate the sloping roof parts - the sloping roof would have been designed to capture rainwater to provide at least some drinking water for those inside the tower if it was beseiged - yet still leave enough roof space for archers to be positioned.
Glue the two end gables into the holes provided - then glue the roof tile sections onto them:
Replace onto the top of the tower BUT DO NOT GLUE IT THERE!
Next, we'll assemble the staircases - there are two of them, one for the outside of the tower and one for the inside:
Glue the two cross beams into the holes in one staircase side:
Slide a staircase piece over the two cross-beams and glue in place, then repeat for the remaining staircase pieces:
Glue the remaining cross-piece in place - then attach the other staircase side:
Repeat for the other staircase.
The outside staircase has a platform at the top:
Glue the small "floor" part to one of the sides:
Then glue on the remaining sides:
The staircases are useful terrain parts by themselves - so I don't usually glue them in place - it's also useful to be able to remove them in-game if they have been destroyed somehow: