There are some unexplained things in this chapter, like journey that Eldric took to went down the floating island. So here are some explanation on how to get below the island
There are two general ways
Using magic, and teleporting to the port situated in the floating island edge;
Using magic, in form of mini flying island, floating down the main floating island.
However the usage of the mini island is starting to be abandoned by the people, seeing as using teleport magic is more efficient and practical.