Explanation
About ad sequencing
Reach and frequency buying has a sequencing tool that allows you to arrange up to 50 ads in a certain order to be shown to an audience. People in your target audience will have the opportunity to see ads in the order you set. For example, ad #1 will be delivered to them before ad #2 is delivered. It doesn't allow you to control whether or not a person has to have engaged with the content you are showing in order to see the next ads in your sequence.
Sequence your ads when you want to tell a story or present information to people in a specific order. For example: If you want to build a narrative with your ads, you can show one ad that tells the beginning of the story first and then show additional ads afterward that continue to tell the story in a set order. Your audience will see ad #1 before they see ad #2, and so on.
Sequencing becomes available after you've uploaded your ad creative and reserved your reach and frequency campaign.
Use sequencing when:
* You want to reach a broader audience with several different ads that tell a story.
* You want to try different ways of engaging a broader audience.
* You want to tell a story about a brand.

* Real PeoplePeople-based measurement enables you to see how well your ads work with real people rather than proxies, such as cookies and device IDs. This understanding allows marketers to measure accurately across devices, publishers, browsers and in stores.
* PersistenceAdvertisers are able to leverage insights from Facebook's 1.45 billion daily, re-authenticated users, so they know they're reaching and measuring over time.1
* ScaleOur solutions provide broad, global cross-environment coverage. We're the only technology built on the insights derived from Facebook's vast community of 2.2 billion monthly active users.2
* DepthMarketers gain access to high-fidelity age, gender and geographic data to perform holistic marketing and measurement at scale.

Explanation
About Actions You Can Measure in Facebook Ads Reporting
An action is activity that happens on your ad (for example, someone watches your video ad) or as a result of your ad (for example, someone views your ad and then downloads an app).
Actions that occur on your ad include link clicks, outbound clicks, post engagement, video views, and more.
Actions that happen as a result of your ad include website conversions, website leads, mobile app installs, mobile app purchases and offline conversions. We attribute these actions to your ad if someone viewed or clicked on your ad within a certain period of time, as defined by your attribution window.

Explanation
Since you are doing in-store campaigns, you want to measure the effectiveness of your Facebook ads through two means:
* Actual performances on the ads themselves based on reach, impressions, and CPM. Keep in mind that you don't want to measure CPC, as you will be measuring performance through offline events.
* Performance on ads through offline events: revenue per user and average order value per user.
For these types of campaigns, you want to make sure you measure your campaigns in two stages. The first will allow you to understand better how much you have to spend to reach a specific audience. The second will allow you to better understand the "direct response" performance on the ads based on actual sales data.