A future time is spoken of as if "days will come." Alternate translation: "there will be a time ... when the plowman" or "in the future ... the plowman" (See: [[rc://en/ta/man/translate/figs-metaphor]])
These are two images of Yahweh restoring prosperity in Israel. This means grain will grow faster than the people can harvest it, and there will be so many grapes, those crushing the grapes will still be working when farmers start planting more vineyards.
Yahweh speaks of himself by name to express the certainty of what he is declaring. See how you translated this in [Amos 2:11](../02/11.md). Alternate translation: "this is what Yahweh has declared" or "this is what I, Yahweh, have declared" (See: [[rc://en/ta/man/translate/figs-123person]])
These two lines mean basically the same thing. The huge amount of grapes and wine in Israel is spoken of as if wine flows down the hills and mountains. (See: [[rc://en/ta/man/translate/figs-parallelism]] and [[rc://en/ta/man/translate/figs-metaphor]])