If you cannot download Ragnarok M Eternal Love on Google PlayStore for some reason, not available in your country, your device is not compatible with this version, or whatever the reason.
The official page of Ragnarok M: Eternal Love provided a direct download link for their APK version of the game, which can be use to install to any Android devices without using the Google Playstore.
Ragnarok M Eternal Love will be available tomorrow, but right now you can pre-download and install it to your phone.
How to Download Ragnarok M Eternal Love APK
You can download the APK straight from their website at www.ragnaroketernallove.com/apkdl
The download size is 1.3GB which include everything in the game.