When you are ready to print click Prepare in the bottom right hand corner. It is recommended that you first check the layer/slice preview. This is located in a drop down near the top of the screen. Change from Solid View to Layer View You can use the slider to preview the slice prior to printing.

When you are ready to print click the Save to File or Save to Removable Drive button in the bottom right hand corner. If you print via a Raspberry Pi (OctoPrint / AstroPrint) choose Save to File. You can then choose where to save the file and later transfer it.

After you have saved the file, Cura will provide you with the file location, name, and the option to eject the memory device.