I (Marcus Green) am no longer maintaining this plugin, but there is an alternative plugin that covers a very similar functionality which can be found here https://github.com/marcusgreen/moodle-report_advancedgrading
Excel spreadsheet export tool for individual component grades for assignments using Marking Guide, Rubric or BTEC Grading
Install from the Moodle.org plugins database at https://moodle.org/plugins/report_componentgrades
Or using git from the command line go to moodle\report then
git clone https://github.com/marcusgreen/moodle-report_componentgrades componentgrades
User documentation https://docs.moodle.org/en/report/componentgrades