First make a backup of the old UI. In case you ever want it back.
Create a new folder on your desktop. name it backupUI or something
Go in your EPW folder > elements.
Find surfaces.pck and interfaces.pck, copy them and paste them in the backupUI folder you just created.
Put that aside, you`ll only need it again if you want the old UI back.
Download the UI
Save it somewhere you'll find it.
Extract with 7-zip or something siimular.
Now copy the surface.pck and interface.pck you just unzipped and paste them in your Epic Perfect World > element folder. (The same folder you copied the backup files from)
It will ask you if you want to replace the old files - say yes.
Close all, start your game as usual, it will do a tiny update that just takes half a minute and its done!
Not a video guide but it might help
Oh yeah if its a russian ui you might have to start it with the elementclient.bat - also to be found in the element folder