Hi Miguel

Here you have a complete sample (just the same described in the dev.liferay.com)  https://github.com/liferay/liferay-blade-samples/tree/master/gradle/overrides/resource-bundle-override

And this is the class, take in account it does not matter the name of the class, the important here is code inside, making reference to the module host whose translations will be "overwritten": https://github.com/liferay/liferay-blade-samples/blob/master/gradle/overrides/resource-bundle-override/src/main/java/com/liferay/blade/samples/hook/resourcebundle/ResourceBundleLoaderComponent.java 

However it seems you want to overwrite a calendar key, if this is the case, you need to wait for the LPS-83494 fix because currently some translation in modules can not be overwritten. 

Best regards,

Jose