If you have a target list of emails that you wanted to send emails to and want to email them in chunks, there are two options that we recommend.
If you wanted to go sequential and break the target list, you can do this in two different ways. You can create a custom field to populate an auto number or just update those records with a sequential number and use that to break up your contacts into multiple chunks in the list view.
Or you can export those contacts using a report (include the salesforce id) and import the individual chunks of the target list into different Salesforce campaigns using the Salesforce data import wizard (this won't create duplicates if you use the salesforce id as the unique identifier).
Here is an article by Salesforce that you can refer to.