A full description of the parameters listed in the fits file can be found in the Appendix of the catalogue paper (Georgakakis et al. 2011). Simple examples of how to select sources with different selection criteria are listed below. The examples use the FSELECT task of FTOOLS but the filter can b≈e applied to any code or scripting language. 1. Select point sources detected in the FULL band with Poisson probability <4e-6. The filter (EML_EXT_ML_FULL<=3 && EML_EXT_ML_SOFT<=3)) selects against extended X-ray sources: fselect infile=xmmsdss_v1.fits outfile=out.fits expr="( ( (PROB_FULL<=4e-6 && PROB_FULL>=0 && EML_DET_ML_FULL>0) && (EML_EXT_ML_FULL<=3 && EML_EXT_ML_SOFT<=3))" copyall=yes clobber=yes 2. Select point sources detected in the HARD band with Poisson probability <4e-6 and with secure optical counterparts (likelihood ratio > 1.5): fselect infile=xmmsdss_v1.fits outfile=out.fits expr="( ( (PROB_HARD<=4e-6 && PROB_HARD>=0 && EML_DET_ML_HARD>0) && (EML_EXT_ML_FULL<=3 && EML_EXT_ML_SOFT<=3)) && LR>1.5" copyall=yes clobber=yes 3. Select point sources detected in the SOFT band with Poisson probability <4e-6, with secure optical counterparts (likelihood ratio > 1.5) and available spectroscopic redshifts: fselect infile=xmmsdss_v1.fits outfile=out.fits expr="( ( (PROB_SOFT<=4e-6 && PROB_SOFT>=0 && EML_DET_ML_SOFT>0) && (EML_EXT_ML_FULL<=3 && EML_EXT_ML_SOFT<=3)) && LR>1.5 && z>=0" copyall=yes clobber=yes