Documents to use the props and its methods

[archercoder]

Hi ,I am quite new to ReactJS. Found this plugin very useful. But when I wanted to use the renderCustomHeader using its example in the documents, I don't know where to import the changeMonth and changeYear method from ? Any advice ?
The current document only shows the examples with body only, but it doesn't show the import headers, Is the changeMonth and change Year belong to standard JS or ES library ? Or is it part of the plugin that I need to import ? How to import them ?