Practically, ERM identifiers for materials can be registered in two ways: i) by creating a request in the GitHub project issue tracker, as explained in a dedicated tutorial at nanocommons.github.io/identifiers/register; or ii) by communication (e.g. email or pull requests) to the NanoCommons team, which is the way most current identifiers have been registered. The second approach works best when multiple identifiers need to be registered together, e.g. at the initial stages of a new project when decisions around the nanomaterials to be utilised in the project are finalised.