Hi @Apple, 

Welcome to the Community! 

Before you sync your Facebook Lead Ads ,which should first be created in Facebook, to your Klaviyo account, you will need to connect a Custom Audience Setting to one of your Advertising Account. Select your business’s Facebook page, then click Connect to Account. You may also skip this section to update Lead Ad Settings only by selecting Skip to Lead Ad Settings, though we recommend setting up your Custom Audience when you integrate your account to get the most out of the Facebook Advertising integration.

If you chose Connect to Account, you will be prompted to add a Custom Audience sync in the next section. Once, you’ve finished this section, I’d suggest you take a look at our helpful documentation on How to Connect Lead Ads to a Klaviyo List. The Facebook integration syncs with Klaviyo every hour.

I’d also suggest checking out this similar post to gain more insight in this integration area!

Hope this helps! 

-Taylor