The process to start farming Destiny 2 Bright Engrams is easy, all you need to do is to reach level 20 with the Guardians. As you are at level 20 you will see that Guardians cannot level up more but they can still earn XP. Now every time you fill the XP bar to the Max you will get a Single Bright Engram. This is how you start farming them. For the early stage you will be able to easily get 3-4 Bright Engrams and then it will be a bit difficult after some time. And if you are tired of purchasing items using the Bright Engrams then you always have the option of dismantling items into Bright Dust, which is the Eververse's specific Currency.