Explanation
For this exercise, you need the following aspects in order to segment your core/saved audience:
1. Age: you definitely want to set up age below 25 years old.
2. Mobile Device User: you need to specify Android as the primary operating system for mobile in order to target just Android users and exclude iOS users.
3. Location: you want to target the specific countries. In this case, Colombia and India in order to reach out to people in those two particular places.

You don't want to use App Store Region as an option to segment as they don't allow you to select specific countries. You are better off selecting countries and Mobile Device User to segment.

The gender and interest for this exercise are irrelevant since you don't have more info on what the mobile app is about.

Explanation
In light of new test results-in combination with new research from Facebook IQ on designing effective video ads for the mobile feed- Facebook has made some updates to its mobile video creative considerations.
Facebook has added a new tip on framing and revised their suggestion on experimentation to encourage advertisers to play more as they explore storytelling through video in mobile feed.
Here are other updated video creative considerations:
* Capture attention quickly. Using colors, themes and imagery that evoke your brand at the start of your video can help people connect the ad to your brand quickly. Consider starting your video with lifestyle and product shots, recognizable spokespeople, action scenes or a vivid background to spark interest.
* Design for sound off. Since most video ads in mobile feed are viewed without sound, it's important to convey your message visually. Showing captions, logos and products can help communicate your message, even in silence.
* Frame your visual story. Producing video for a small screen requires consideration of dimension and scale. Play with zoom, crop and overall visual composition to make sure your story is told well on a small screen.
* Play more. There's no universal solution to building brands or driving actions with mobile video, so keep experimenting, testing and iterating to learn what works for your brand and audience.

Explanation
You can create ads targeting people by customer lists. One of the data sources you can use is mobile advertiser IDs.
* Apple's Advertising Identifier (IDFA): An advertising ID that Apple provides as part of iOS in its ads framework.
* Android's Advertising ID: An advertising ID that Google provides as part of Google Play services.
* Facebook User ID: If people are logged in to your app via Facebook, you can use their Facebook User ID for targeting.
You can't run Google IDs currently on Facebook to identify users.

Explanation
The following scenarios are examples of link clicks that may not result in a landing page views:
* A person clicks a link accidentally and closes the page before it gets a chance to load
* A person clicks a link intentionally, but the page takes too long to load and the person closes it before it finishes If I can optimize for landing page views, should I?
It depends on your goal and/or ad format:
* If your goal is to get more traffic on a specific page (or specific pages) of your website: We recommend landing page view optimization over link click optimization, since the former can improve traffic quality. We especially recommend it if you're trying to get people to land on a page (or pages) on their mobile devices.
* If your goal is to get more conversions: We recommend trying to optimize for conversions first.
However, conversion optimization does not work for everyone. A conversion-optimized ad set needs to get about 50 of the conversion it's optimized for per week (though getting even more is better) to have a chance at being effective. If your ad set doesn't get that many per week, landing page views could be an effective alternative. They're also a good choice if you don't have lower-funnel events (ex: a purchase conversion) set up with your pixel yet.
* If your goal is to get more people viewing more content on your site overall (not landing on specific destination URLs of ads): We recommend optimizing for ViewContent conversions instead of landing page views, since the former optimizes for people to view any page on your site with that event added.
Note: This means you have to add that specific event to every page you want people to view. For landing page view optimization, you only have to have the pixel base code on every page you want people to land on (we only optimize for people landing on your website after clicking from your ad).
However, keep in mind that this type of optimization is not available for ad sets in Traffic campaigns.
* If you're using an ad format (ex: Canvas, Offers, Messenger) that takes people to a Facebook page or video: We recommend optimizing for link clicks, not landing page views.