The main condition is you need to collect 100 target events in the same country. This means you need to run test ad campaigns using standard Facebook targeting options (location, gender, audience behaviors, etc.) that you expect to work for your app. Test as many options as is sensible. Once you have your first 100 valuable events, you can create a Lookalike Audience of people similar to those who performed the event and run your marketing optimization based on them.

Go to your Facebook Business Manager, open the main menu in the upper-left corner, and click on the Audiences section 

Facebook Ads Menu

Click the Create Audience button and select Lookalike Audience

Create Audience

Now you can set up your audience based on several factors. The first section requires selecting the source for your Lookalike Audience. In our case, it’s simply your mobile app.

Create a Lookalike Audience. Step 1

Choose the event that your Lookalike Audience will be based on in the next section. For example, Trial Start, Subscription, or Purchase. Do not forget that you need to have at least 100 events/people in the same country.

Create a Lookalike Audience. Step 2

Then you need to define your target-audience location. It’s probably a good idea to start with Select All to make the potential targeted audience as broad as possible, but you have to consider your apps’ properties.

Create a Lookalike Audience. Step 3

The last step is to select your targeted audience size. This can range from 1% to 10%. A 1% setting is the most precise. When you increase the percentage, you expand the audience and add more people who look somewhat like your valuable users but may differ more. Remember, thе smaller the audience size, the more similar your new Lookalike Audience will be to your existing valuable subscribers.

Create a Lookalike Audience. Step 4

After you finish with the steps above, click the Create Audience button. Now you can go back to your Ads Manager and create your first Ad Set using Lookalike Audience targeting.