All the code in https://github.com/collective/collective.migrationhelpers is meant to be used in your own upgrade-steps. If you don't know what that means I suggest you read https://training.plone.org/5/mastering-plone/dexterity_2.html#upgrade-steps and https://docs.plone.org/develop/addons/components/genericsetup.html#upgrade-steps.
Simple examples how they are used in real life for upgrade-steps that migrated https://www.plone.de from Plone 4.3 to 5.2 can be found in https://github.com/collective/plonesite.de/blob/master/src/plonede.policy/plonede/policy/upgrades.zcml and https://github.com/collective/plonesite.de/blob/master/src/plonede.policy/plonede/policy/upgrades.py.
More examples are mentioned in Small project migration with customized barceloneta.