XCOM 2 is filled with various types of currencies and materials that you’ll need to do things throughout the game. But the most important of those currencies is Intel. Intel can be gained a different number of ways. You can gain it each month from the Council, and you can also gain it from Scanning remote areas that pop up on your map as the days pass.
You can also gain Intel by completing certain Research tasks like Analyzing ADVENT Datapads and other equipment that you team picks up from the various missions you’re sure to undertake. Perhaps the easiest and most fruitful way to gain Intel, however, is to return the Avenger to the Resistance Base and Scan from there.
The only real downfall to this, aside from boring yourself just sitting there watching that line spin in circles, is that the Avatar Project waits for no one, and each day that passes will push the timeline forward without you being able to stop it. This makes scanning from Resistance HQ something that should be done in moderation, as you wouldn’t want to let the Avatar Project get too far ahead.