This archive contains a unique DRS file (itf_custom.drs) that contains all DRS resources from both data/interfac.drs and data2/interfac.drs files.
This file version is for 1920x1200 screen resolution.
Put itf_custom.drs in data/ sub-folder in your AOE installation folder.
If you are using latest version of RockNRor, the game should automatically detect the screen resolution to use.
If the game starts in 640*480 or 800*600, just go to game options and choose the maximum resolution (don't worry if the label says it's 1024*768)
Then the game should remember your choice for next times you run the game.
With RockNRor, you can add any number of DRS, whose contents will be added (of overload) to the standard DRS files. This way, you never corrupt original installation files.
There is no reason putting "interface" graphics in separate files.
However you might want to use separate files for mods, for example (one DRS files for interface graphics, one for custom units graphics, etc).