Basically, what do you need is Internet Download Manager, then feel free to download any as you wish ^^~
1) Go to myasiantv
Search for the drama/ movie you're looking for in the box. For example, 'Goblin'.
2) Just click 'DOWNLOAD' button
3) Click any episodes, example 'Goblin 1'
4) Click 'OPENLOAD'
5) Click play button as in red box
If the button 'Download this video' (as below) not pop up within 2-3 secs, just click until the button turned blue and IDM dialog box appear.
6) Then just click 'Start Download'.
Good luck guys~ ^_^