You can read through this paper and understand about the tool about how it can be used and interpreting the results Article Krona: Interactive Metagenomic Visualization in a Web Browser
. And No, you don't need any programming language if you just want to visualise the data without much manual tweeks. You can download the readymade excel template and use it as per the direction and you will get the krona plot as an output. https://github.com/marbl/Krona/wiki/ExcelTemplate