How are lookalike audiences created on Facebook?

Lookalike audiences on Facebook are created by using a source audience, which is a custom audience that you've previously created based on your customer data or engagement on your Facebook page or website. Here are the steps to create a lookalike audience on Facebook:

1. Go to the Audiences dashboard: In Facebook Ads Manager, navigate to the Audiences dashboard by clicking on the three horizontal lines in the top left corner, then selecting "All Tools" and "Audiences."
2. Create a custom audience (if you haven't already): If you haven't already created a custom audience based on your customer data or engagement on your Facebook page or website, you'll need to do so before creating a lookalike audience. To create a custom audience, click on the "Create Audience" button and select "Custom Audience." Then, choose the source of your customer data, such as a customer file or website traffic, and follow the prompts to create your custom audience.
3. Create a lookalike audience: Once you have a custom audience, you can create a lookalike audience by clicking on the "Create Audience" button and selecting "Lookalike Audience."
4. Choose your source audience: In the "Source" section, select the custom audience that you want to use as the source for your lookalike audience.
5. Choose your target country: In the "Location" section, select the country where you want to target your lookalike audience.
6. Choose your audience size: In the "Audience Size" section, use the slider to select the size of your lookalike audience. Facebook allows you to create lookalike audiences of different sizes, ranging from 1% to 10% of the population in the country you're targeting. A smaller audience (1-2%) may be more accurate but less scalable, while a larger audience (5-10%) may be less accurate but more scalable.
7. Name your audience: Give your lookalike audience a name that reflects the source audience and targeting criteria you've selected.
8. Create your audience: Click the "Create Audience" button to create your lookalike audience.

Once you've created your lookalike audience, you can use it to target ads to new customers who are similar to your existing customers. Keep in mind that it may take some time for Facebook to create your lookalike audience, especially if your source audience is large or complex.