How do you know the location to farm materials?

How do you know where to farm the other materials in Arknights? This can be important since some parts of the game require you to strengthen your characters through leveling up, promotion, upgrading skills, and more. Some materials like those in promoting, can be farmed in the game's story line.

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Check the Item's description

Thankfully, you can check an item's location by looking at your item description through the depot, or by clicking the item long enough in any interface that will show its description. There's a "How to Obtain" section there that will list which stage these items are dropped.

The items that you farm can be converted to advanced versions in the shop. If this is needed, the item description will indicate which facility in your base that can process your items.