just a tool to prepare model files and tell printer what to do with ?
Yes. It is the "slicer" that converts the 3D models you import into code that the printer uses to extrude the layers. It has a number of settings for layer thickness, infill density, support structures, etc. You save the resulting "zcode" file to an SD card which you transfer to the printer. In the next firmware I think you will be able to send it directly to the printer via wifi.