To build this mount you'll need 7 items looted from bosses of the Oramond Factory Raids and of the Hero of Rathleton Quest. You must also have completed 4 specific tasks in the Oramond Quest at least once before building the Glooth Glider. Once you obtain the Glooth Glider Blueprint, you can use it to check what items and tasks you still require to complete the mount. Note that you can only build the mount if you have completed the Hero of Rathleton Quest yourself, just buying them items will not be enough.

You need the following items to construct the Glooth Glider:

These tasks must have been completed at least once:

Once you have all items and all tasks, find Peremin in the Underground Glooth Factory, here, and ask him to build the mount for you, then say yes.