If it tests good Monday or Tuesday there will be an update to Minion where it will detect all 3 versions of ESO and list them under the game list automatically.
However if you want to do it now manually:
1. press the "Add Game" at the bottom of the game list in Minion
2. Select ESO
3. Find the Users folder and expand it using the little triangle
4. Find the folder with your windows user name and expand it
5. Find the Documents folder (NOT My Documents) and expand it
6. Find the Elder Scrolls Online folder and expand it
7. Find the liveeu folder and expand it
6. click on the AddOns folder
7. press the select button and it should add it to the game list
Now keep in mind you will now have two ESO games in your game list and they will be named identical. The only way to tell them apart is to look at the addon path under options right now. The update coming out next week will append EU or PTS to the end of the name so its easy to tell them apart.