These roofs are a little tricky to put together. The best way to do it is to lay all of the tower roof panels on a flat surface, interior sides facing up, to create a circle. Make sure they are butting against each other tightly. They will not create a complete circle, but an open ended circle. Use masking tape to hold the panels tightly together. The masking tape needs to be applied along the top, middle and bottom in order to make sure that the panels do not come apart. Do not place the top masking tape too close to the edge as you will need leeway to place the top roof.
Once the panels are held by the masking tape, lift them gently and position them, standing upside down, to create a cone. This is what the tower roof is supposed to look like upside down. Use masking tape to hold the ends of the cone together, so it doesn't come apart and keeps it shape.
Then slide the Tower Roof Top into the "cone" you have created and run glue along its joints. This will help stabilize the structure. Do not remove the masking tape from the interior of the tower yet, it's not glued together. Use glue along the exterior joints of each panel and wait for the structure to dry overnight, as it is very fragile to do anything else with.
On the following day, you can remove the masking tape and finish the interior of the tower roof. It will be visible from the inside of the dollhouse. You can cover it with ceiling paper or a mural if you like but I just painted mines white. If you are just using paint like me, you will need to fill in the gaps between the panels with spackling compound, lightly sand and then give it a second coat.
After the tower roof is completely finished on the interior, you can slide in the Tower Roof Bottom and glue it in place.
