If you have set an Audience that you know that you are going to want to re-use you can save this Audience as a template. This enables you to load this Audience into another project.
To save your Audience as a template you simply set up your Audience statement and then when you are done and have saved this you click the three dots next to the save button and then choose Save as a template.
This brings up a popup where you get to enter a name for your template and also an optional description.
Enter the information and click Save.
You can now load this Template in another project by opening Audience and then clicking the three dots next to the Save button and choosing Load template.
You will then get a list of your saved templates that you can load. You do this by clicking the cog icon on the desired template and choosing Load.
This will populate the Audience in your new project. You can now either save this as is or make some adjustments if you wish.