It is not clear whether Amos is speaking about God, or God is speaking about himself. If God is speaking about himself, it can be translated with the words "I" and "me." Alternate translation: "I who form the mountains ... reveal my thoughts ... is my name" (See: [[rc://en/ta/man/translate/figs-123person]])
Possible meanings are 1) God causes the day to be very dark with thick clouds. Alternate translation: "makes the morning dark" or 2) God causes time to pass, so every day becomes night. Alternate translation: "makes morning and evening"
God ruling over all the earth is spoken of as if he walks on the highest places of the earth. Alternate translation: "rules over all the earth" or "rules over even the highest places of the earth" (See: [[rc://en/ta/man/translate/figs-metaphor]])