After the initial scenes of Shadow of the Tomb Raider, you will find yourself in a location called the Peruvian Jungle. Two first challenges await you in this location. They're not complicated - you just have to collect the right resources. You can use the raw materials collected during these challenges to create equipment upgrades.
To start the Ruffled Feathers challenge you must go to the area marked on the map above. In the marked area you will find both challenges for this location. If you want to begin a challenge you have to complete the first element or task of a selected challenge. If you don't do this, the challenge won't start (it won't be marked on the map).
In the Ruffled Feathers challenge you have to walk around the map and shoot down feather bags. These are hung on trees in the jungle. To shoot down such an object just use your bow or any firearm available. You are not able to climb the tree and cut off the bag to the ground.
You have to shoot 4 bags to complete this challenge. There are more of them on the map, which may serve as additional resources later.
If you want to start the challenge of Flower Picker you have to go to the area marked on the map above. There, you will find both challenges of this location. If you want to start a challenge, you need to perform an activity related to the challenge, in this case - collect the first flowers. If you don't do this, the challenge will not appear on the game map.
The flowers needed to complete this challenge grow exclusively on trees. This means that they cannot be confused with any other vegetation available in Shadow of the Tomb Raider. These flowers have a strong blue color. To take them away you need to jump on a branch of the tree, you can't gather them from the ground.
If you want to finish the Flower Picker challenge you have to collect 5 blue plants. There are many more of them in the game, which can serve you later as an additional source of raw materials.