This page explains how to find the Pumaag Nitae shrine.
How to Find the Shrine
Go east on the road that goes past Lake Tower. Eventually you will reach a fork in the road in the Faron Woods. Go left at the fork. The road will go past this shrine.
How to Solve the Shrine
In this Minor Test of Strength, the Guardian Scout wields a Guardian Sword and Guardian Shield. After you kill the Guardian, open the chest to get a Boomerang.