If you are checking Marker Tracking (i. e. Digitizing), select the [Your prefix]xyzpts.csv file that was generated from marker tracking.
If you are checking Calibration, select the framspec.csv file for the type of cube you used. This file contains the known locations of the beads in the cube. If you don't have this file, it can be downloaded.
Select xyz Translation under Data Type, depending on the version you have.
Select new sphere under Object Options, depending on the version you have.
You can change New Object Scale to something smaller to make sure the markers in the Xray Image will show up behind the imported points. (e. g. 0.5 or 0.1)
If you are importing unmoving markers (such as for checking Calibration), uncheck Rows are Time Series. Otherwise leave it checked.