These steps should be completed in your destination environment.
You will be required to set up a Service Account. Please refer to the Setting up the Service Account and enable the APIs within Google Workspace for CloudM Migrate article.
CloudM Migrate Hosted makes migration as simple as possible. The only other prerequisite is the installation of the CloudM Migrate Hosted application. When accessing CloudM Migrate Hosted for the first time, you will be prompted to install the app, simply authorise and you are all set.