Validate XML file with schxslt and xslt3 (saxon-js)

Question

I am struggling to understand the steps to validate an XML file with schxslt-cli, xslt3, and saxon-js. These are the files that i use:

• schxslt-cli.jar + stylesheet (https://github.com/schxslt/schxslt/releases/tag/v1.9.5)
• CEN-EN16931-UBL.sch (https://github.com/OpenPEPPOL/peppol-bis-invoice-3/blob/master/rules/sch/CEN-EN16931-UBL.sch)
• PEPPOL-EN16931-UBL.sch (https://github.com/OpenPEPPOL/peppol-bis-invoice-3/blob/master/rules/sch/PEPPOL-EN16931-UBL.sch)

Steps that i tried:

1. Compiled Stylesheet: java -jar schxslt-cli.jar -s CEN-EN16931-UBL.sch -d schxslt/2.0/pipeline-for-svrl.xsl -o output.xsl Not sure if the commands that i used are correct, because the resulting stylesheet is too simple

2. xslt3 -xsl:output.xsl -export:output.sef.json This gives error:

Error XTSE0150 on line 1 in Artifacts/output.xsl:
  Simplified stylesheet root element lacks @xsl:version
Failed to compile stylesheet

I am also not sure of what to do next, should I use SaxonJS.transform() on the SEF file?