Steam notifications are nice, but in AoE2:DE they block the minimap. This is annoying, so let's fix it in 4 easy steps:
Step 1
Navigate to C:\Program Files (x86)\Steam\resource\styles or wherever your steam installation folder is located.
Step 2
Right-click gameoverlay.styles and click open with, then choose notepad.
Step 3
Change the text from BottomRight to TopRight, or whatever your preference is.
Step 4
Important: after the two forward slashes // type any 3 characters (exactly). In the example, i have typed 123. This will ensure the file size doesn't change, so Steam doesn't override your changes.
That's it!
Alternatively, you could just turn off all steam notifications entirely in steam's settings