You've created an audience and now you want to further segment clients in that audience into another. Easily do this by following the below steps.
Choose Marketing & Autopilot from the left menu which is highlighted in magenta below
Choose Audiences
Search for the audience by entering the audience name or a portion of it into the search bar and click the magnifying glass
Choose the Audience by clicking on the name
Search for the contacts in two ways:
Enter their name in the search bar, click the magnifying glass, then choose them by putting a tick in the box to the left of their name
Or perform a quick search to find all contacts within the Audience that match certain criteria
Once you have chosen all of the contacts you wish to put in the new Audience, click Save Audience
You can then create a New Static Audience or Add the contacts to an Existing Audience
If you Create a New Static Audience you will be asked to name it:
If you choose to add the contacts to an Existing Audience, you will be asked to choose the audience