I'm working with [this downloadable shapefile](https://data.nola.gov/Geographic-Reference/NOLA-Addresses/div8-5v7i) that has X Y coordinates. They are akin to `'3672187.92698000, 534175.72095400'`.

I would like to convert them to longitude latitude so they are more like `'-90.097017, 29.963176'`.

I've seen this [question tackled using ArcMap](https://gis.stackexchange.com/questions/43922/convert-x-y-state-plane-coordinates-to-decimal-degrees) however I don't have that software. I was able to download and install [QGIS](http://www.qgis.org/) but I am unfortunately perplexed by its complicated interface. Would like to do the conversion with it, if possible.