Here "from above" is metonym that represents "heaven," which represents God himself. The abstract noun "wisdom" can be stated as "wise." Alternate translation: "But when a person is wise according to what God in heaven teaches, he acts in ways that are first pure" (See: [[rc://en/ta/man/translate/figs-abstractnouns]])
Here "good fruits" refer to kind things that people do for others as a result of having wisdom from God. Alternate translation: "full of mercy and good deeds" (See: [[rc://en/ta/man/translate/figs-metaphor]])