Dear Long,
What you are looking to do is to “Segment” the EBSD data into ‘Features’ (grains) and then export that model to a file type that PRISMS can understand. With a single 2D slice of EBSD data in the form of a CTF file you can use the “Read Oxford Insta. EBSD Data (.ctf)” filter. After that you will need to process the data to your own satisfaction. You may need/want to run filters that can remove the un-indexed points and fill in the data from surrounding scan points. After this initial cleaning step, you then can run the “Segment Features (Misorientation)” filter to create the grains. This step can sometimes result in grains that are too small or too big based on your knowledge of the data. There are filters to remove those small/large grains.
Once you get the data to your liking then you can try and export the data through a few of the various file formats. I am not familiar with what PRISMS needs for in input file.
There are a few example pipelines such as the "(08) Small IN1090 Full Reconstruction” and the “aptr12_Analysis” that show various ways to clean up these kinds of scans.