In the CubeX software, just select "Open" to load a helper disk. If you need more disks, just select open again and repeat that for as many disks you might need. Then select open again to load your part. In the top view, select a helper disk and place it on outside edge(s) of part. See picture below as example. After the print, the helper disks can be easily cut away.
Note: If you scale the helper disk, make sure you don't scale too small/thin, otherwise might get a print file error because the disk height is thinner than you print height resolution.
For printing larger PLA parts or almost any ABS part, save up some money and get the heated print bed from GRM products (See other post with a review of the heated print bed).
It is not cheap, but well worth the money. No more part warping, it works really well.
See also the "Model build setup" blog on this site.
Here you can download the helper disks:
Helper disks zip file