To install any of these plugins:
tutor plugins install https://raw.githubusercontent.com/umairahmadh/Edx-tutor-plugins/master/FILE_NAME_OF_PLUGIN_YOU_WANT.yml
Eg, tutor plugins install https://raw.githubusercontent.com/umairahmadh/Edx-tutor-plugins/master/combinedloginregostration.yml
Enable it
tutor plugins enable PLUGIN_NAME Run tutor config save
Run tutor local quickstart