en_tn/1ch/29/22.md

before Yahweh

This is an idiom. Alternate translation: "in honor of Yahweh" (See: rc://en/ta/man/jit/figs-idiom)

a second time

This means that they anointed him and declared him as king. The first time is described in 1 Chronicles 23:1.

anointed him with Yahweh's authority to be ruler

To do something with "Yahweh's authority" means to do it on his behalf and with his approval. Alternate translation: "anointed him to rule over Israel on Yahweh's behalf" (See: rc://en/ta/man/jit/figs-explicit)